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Kepler Guest Observer Program

Cycle 4 (2012) Accepted Guest Observer Programs

Roi Alonso
Observatory of Geneva

Observations of a very rare system of a white dwarf with an M star eclipsing component that is accessible to Kepler may make this target the cornerstone of its class. We propose to continue 1-min cadence observations of this post-common-envelope object to 1) obtain very precise orbital parameters, 2) study unsolved issues related to the flare activity on the M companion, 3) investigate the evolution and overall distribution of magnetic active regions in any of the components, 4) search for the secondary eclipse that serves to constrain the eccentricity of the system, 5) perform a study and interpretation of the O-C residuals of the 1040 eclipses/year to be obtained with unprecedented precision of 4.5 s/eclipse, and 6) search for pulsations of the WD component.

Victoria Antoci
Aarhus University

HD 187547, a delta Scuti star discovered by the Kepler satellite, shows the first evidence for solar-like oscillations in a delta Scuti star (Antoci et al. 2011). Theoretical models predicted (Houdek et al. 1999, Samadi et al. 2002) both solar-like and opacity driven oscillations to be present in stars located on the cool border of the classical instability strip. To validate this theory, we require more than just one such star. In this proposal we apply to observe two more stars showing similarities to HD 187547. To clearly distinguish between closely spaced coherent modes and stochastic oscillations we need long data sets.

Tom Barclay
Bay Area Environmental Research Institute

A fundamental goal of modern stellar astrophysics is to accurately model stars of different masses and evolutionary stages. Our ability to test and improve stellar models, however, relies crucially on the independent information available to constrain the model parameter space. We propose to observe a small sample of the brightest solar-type stars in the Kepler field which, unlike most stars observed by Kepler, have strong constraints on their fundamental properties from complementary observational techniques such as astrometry, interferometry, and high-resolution spectroscopy. The key goal of the proposal is to use asteroseismology, the measurement of stellar oscillations, in combination with complementary observations to fundamentally test and advance models of stars. Oscillations will be measured using Kepler data, and complementary information will be extracted from the literature and dedicated ground-based follow-up observations. Observations will then be compared to state-of-the-art models using different input physics. The improved models will allow us to characterize fainter stars for which complementary information is unavailable, and hence aid complementary projects such as the characterization of exoplanet host stars or galaxy population studies.

Tom Barclay
Bay Area Environmental Research Institute

In the summer of 2011 we initiated the RATS-Kepler survey to identify targets in the Kepler field which showed a photometric variation in their optical flux on a timescale shorter than one hour, with a particular emphasis on the shorter period end of this range. We have identified several thousand variable objects in our data and have selected two dozen targets which we bid for Short Cadence observations using Kepler. These sources fit into a few different variability classes: pulsating white dwarfs, roAp and delta Scuti stars, SX Phe stars, flare stars and eclipsing binaries. With each class we are sampling from a new parameter space. We include in our sample only the second variable hydrogen white dwarf found in the Kepler field, the first hot pulsating pre-white dwarf, a sample of high amplitude delta Scuti type pulsators, the first selection of SX Phe variables to be observed by Kepler and the shortest known period eclipsing binary stars. We will use these observations in order to perform asteroseismic analysis of the pulsating stars and to measure changes in the orbital period of the the eclipsing binaries.

Sydney Barnes
Space Science Institute

This project aims to use Kepler to perform the first statistically valid determination of the Milky Way's star formation rate history in the Solar vicinity over the past 5 Gyr, and to identify possible individual star formation episodes in the Cygnus-Lyra direction probed by Kepler. This is a long-standing problem in Galactic astronomy, and one that can now be addressed because of Kepler's unprecedented precision and the development of the technique of gyrochronology. Ground-based observations are insensitive to the small photometric modulations routinely observed by Kepler for very old stars, the latter allowing their rotation periods and thus gyro-ages to be determined. From the ground, it is thus impossible to probe lookback times greater than Hyades age (600 Myr). Furthermore, ground-based surveys do not allow the control and understanding of the data, including selection effects, possible with Kepler. Uncertainties in commonly used isochrone ages are too large to be useful, and asteroseismology is unfeasible for the large sample including thefainter and unevolved star required for this project. Kepler will be used to measure the rotation periods for a large sample of single main-sequence stars for which our team has already performed extensive time-series ground-based spectroscopy using the Hectochelle spectrograph on the MMT. This preparatory work is providing an exceptional target list for the proposed study. These rotation periods will be transformed into precise ages for the stars using gyrochronology, a new distant-independent method for determining the age of a field star from its rotation period. That age precision, far better than that of isochrone ages, enables this project. Variations in the numbers of stars as a function of age provide the star formation history. A proof-of-concept study is included in the proposal to demonstrate feasibility.

George Benedict
University Of Texas, Austin

Past experience with any device collecting photons from stars has shown that good photometry predicts good astrometry. While Kepler has demonstrated spectacularly good photometry, it has yet to yield even average quality astrometry over more than one 90 day time span, one "quarter", during which time Kepler remains at a set roll angle with respect to the sky. Concentrating on one test field for which we have already demonstrated high-precision (1 millisecond of arc) astrometry with a Hubble Space Telescope Fine Guidance Sensor (FGS), we propose to devise a methodology for extracting astrometry with a precision and accuracy commensurate with the world-class photometry. The techniques we devise can be then applied to any other set of targets. For this demonstration, our input catalog will contain every star on any CCD containing RR Lyrae. The proposal contains the results from a small pilot study of the RR Lyrae field to demonstrate our ability to access and model Kepler positional data. The preliminary results, even in the absence of the proposed calibrations, give us confidence that at least excellent proper motions could be obtained from Kepler. Once we have calibrated pairs of CCDs, we will press on to determine parallaxes.

Alexander Brown
University Of Colorado, Boulder

Starspots on late-type stars are a direct manifestation of the photospheric emergence of strong dynamo-generated magnetic fields and are excellent tracers of the magnetic field distribution during both the life-times of individual starspot groups and over the course of magnetic activity cycles. We propose to extend our Cycles 1/2/3 projects of 30 minute cadence Kepler photometry, in which we are investigating how activity phenomena such as the growth, migration, and decay of starspots, differential rotation, activity cycles, and flaring operate on single and binary stars with a wide range of mass (and hence convection zone depth). Our existing Kepler data shows a rich variety of photometric variability including starspot rotational modulation, pulsations (both simple and very complex), flaring, and eclipses. Our proposed Cycle 4 sample of 325 late-type stars was selected based on our GALEX FUV/NUV imaging of the Kepler field (first 220 stars in Target List), the first half of our XMM Large Project X-ray survey of 1 sq. degree of the field (next 35 targets), and stars being observed in our optical MMT and WHT multi-object spectroscopy programs (final 70 targets). Accurate measurements of starspot distributions and spot filling-factor maps can be obtained from the Kepler photometry using our newly-developed and successfully verified light-curve inversion methods that fully utilize the powerful diagnostic capabilities of Kepler time series data. We directly fit for the differential rotation that is easily measured from Kepler data, and this provides well determined starspot positions in both longitude and latitude. A full suite of supporting high resolution optical echelle spectroscopy is being obtained, using the MMT and Apache Point Observatory telescopes (in the SW USA) and the NOT and WHT telescopes (on the Canary Islands), to accurately determine the stellar parameters, including effective temperature, surface gravity, and projected rotational velocity, to identify stars that are spectroscopic or eclipsing binaries and measure their radial velocity curves, and to measure molecular bands (TiO, MgH) that provide an independent absolute measurement of the total starspot coverage and spot temperatures. Our supporting X-ray imaging commenced in 2011 with an XMM Large Project and simultaneous HST UV spectroscopy/Chandra X-ray imaging of several Kepler targets is scheduled during 2012. Our sample includes stars for which Doppler imaging, both conventional and magnetic, is feasible using current technology.

Jennifer Cash
South Carolina State University

RV Tauri stars are luminous, supergiant variables with periods of pulsation that are sometimes predictable and sometimes not. Their lightcurves show alternating deep and shallow minima with a primary period of variability in the range of 30-150 days while their spectra vary across several spectral types. Semiregular (SR) variables show some periodicity, but are even less regular than RV Tauri stars. Both the RV Tauri and SR categories contain members that also exhibit Long Secondary Periods (LSP). RV Tauri and other SR variables occupy the region of the HR Diagram between the Cepheid instability strip to the left and the long period Mira types to the right. The evolutionary status of these objects is uncertain and an adequate explanation of the changes in their spectra and light curves is lacking. The presence of a number of RV Tauri stars in the Local Group of galaxies and their potential use in distance calculations adds cosmological significance to better understanding their luminosities and other characteristics. Investigations of RV Tauri and SR stars for possible non-radial modes associated with the LSPs may resolve current uncertainty about the underlying cause of these features. We propose to combine the efforts of two research groups from Cycles 2 and 3 into a single program and ask to continue to observe thirteen of these objects in Cycle 4. The additional observations will be combined with the Cycle 2 and 3 data as well as archival data from Cycle 1 to form the long base line needed to determine the presence of LSPs, related higher order non-radial modes, the stability of the light curve features over time, as well as the level of amplitude and period variations occurring in the SR stars. The light curve analysis will be supplemented with ground-based spectroscopic and BVRI photometry to map the changes in Teff and log(g) of the stars as a function of the phase of pulsation determined from the Kepler data. Future collaborations with a team of modelers will allow us to expand on our phenomenological approach. This proposed research is relevant to the stated objective of the solicitation for the acquisition and analysis of new data that uses the high-precision photometry of Kepler for asteroseismology and other variability studies of Galactic sources. This in turn fits NASA's mission to pioneer the future in scientific discovery, in particular the Astrophysics Division's Focus Area for Stars that includes understanding how stars form and evolve. The NASA Strategic Plan and Goals for 2006-2016 include Sub-goal 3D to which this proposal is relevant "Discover the origin, structure, evolution, and destiny of the universe, and search for Earth-like planets."

Jonas Debosscher
Catholic University of Leuven

This proposal is an updated resubmission of GO30017, which was accepted in cycle 3. Our goal is to establish the simultaneous detection of uniform period spacings and rotational frequency splittings of nonradial gravity mode oscillations in a sample of carefully selected bright (i.e., Vmag below 13) F-type pulsating main-sequence stars, which are representative of massive host stars of exoplanetary systems, with the Kepler satellite. This will allow to deduce if rotational mixing near the stellar core is the cause of deviations from period spacings and/or if other yet unknown mixing processes occur. Additionally, we will determine the internal angular momentum distribution from the stellar core to the surface for all stars with rotational splitting. We plan to use the novel method we recently developed after the first detection of such period spacings of gravity modes of a main-sequence pulsator, based on 150 consecutive days of high-precision space photometry gathered with the CoRoT satellite (Degroote et al., 2010, Nature, 464, 259). The small deviation from the spacing uniformity of the star HD50230 allowed to deduce the occurrence of a chemically inhomogeneous zone adjacent to the stellar core of this star. The CoRoT data have a too short time base to allow the additional detection of rotational splitting of the gravity modes. This prevented us to deduce the internal angular momentum distribution inside the star despite the readiness of the methodology. We shall overcome this limitation with Kepler data for a sample of 69 F-type gravity mode pulsators discovered in the public Q1 Kepler data. This will provide a seismically calibrated law for the near-core mixing and angular momentum distribution in main sequence stars, thanks to their gravity modes which penetrate all the way from the core to the surface.

Pieter Degroote
Catholic University of Leuven

This proposal aims to understand what is going on in hot pulsating B stars in the Kepler FoV, by observing one carefully selected very bright known variable, with a B1 spectral type, making it the earliest spectral type observed with Kepler. Monitoring this target during one year will deliver the best photometric data sets available for the modelling of any hot B star in terms of duration and signal-to-noise. We shall perform simultaneous high-precision high-resolution spectroscopic measurements with the HERMES spectrograph at the Mercator telescope, to which we have guaranteed access. There is no risk attached to our proposal, given that the stars are known to be variable at mmag level. We are thus sure to have a variable hot B star, a primer for Kepler. In order to identify the dominant observed modes, we shall set up a long-term high-resolution spectroscopy campaign with the HERMES spectrograph attached to the 1.2m Mercator situated at La Palma, Canary Islands, to which we have permanent access. Our proposal is very relevant for the improvement of massive star models and will therefore have a large impact on that field of stellar evolution, as well as on any topic in astrophysics that relies on it.

Rick Edelson
University of Maryland, College Park

The precision and sampling of Kepler AGN light curves are more than an order of magnitude superior to the best obtainable from the ground. Our observations of four AGN (Mushotzky et al. 2011) yields power spectral density functions (PSDs) that are well-described as power-laws which are much steeper than previously measured in both the optical and x-rays, and steeper than expected from AGN accretion disk models developed to explain previous data sets. These steep PSDs must show a break, most likely on time scales of months, or the total variability power would diverge. Our latest analysis yields a tantalizing indication of just such a break in the best-observed source, but this has not yet been detected in other, shorter light curves. This long time scale suggests that the observed optical variations are driven by viscous instabilities in the accretion disk. The only way to confirm and define this break is by lengthening the data train with continued Kepler observation. We propose continued and new Kepler monitoring of 85 AGN and AGN candidates spanning a wide range of luminosity and black hole mass. Measuring the break in such sources would allow a search for the expected correlation between black hole mass and time (and therefore size) scale. Such a correlation, which has already been seen in the x-rays, would yield further insights into the physical processes occurring in the disk. We will also use Kepler data to measure the temporal cross-correlation between optical and x-ray variations in individual AGN. This can provide a crucial observational link between the disk and the putative hot corona. If an interband lag is detected, it would yield a direct estimate of the size scale of the accretion disk. Also, correlations with ground-based emission-line light curves could permit improved reverberation mapping of the larger broad-line region. Determination of the first high-quality optical PSDs and x-ray/optical correlations will allow us to test the predictions of accretion disk theory and models of reprocessing and feedback between thermal (disk) and non-thermal (corona/jet) emission sites in the central engines of AGN. These proposed Kepler AGN light curves will leave a lasting legacy that will not be surpassed for many years to come.

Michael Fanelli
Bay Area Environmental Research Institute

We propose to continue monitoring ~200 of the brightest galaxies located within the Kepler field of view - the Kepler Galaxy Survey. The proposed survey will be sensitive to both continuous variability, especially low-level variations from embedded active nuclei, and random episodic events, such as supernovae. Our primary objectives are (a) to explore the photometric stability of galactic systems with Kepler's unique blend of high precision and continuous monitoring, (b) quantify the existence and amplitude of AGN signals in galaxy cores, (c) provide a direct measure of supernovae rates across galaxy types, and (d) quantify the early brightening of supernova as the explosion rises to peak luminosity. Defined by a J-band magnitude limit, these 200 galaxies encompass a range of morphologies and are located across the field-of-view. Given the Survey's source luminosities spatial distribution these data will form a fundamental temporal baseline for extragalactic investigations with Kepler.

Peter Garnavich
University Of Notre Dame

The progenitors of type~Ia supernovae remain a mystery despite their importance as fundamental distance indicators. We still do not know if type~Ia explosions come from single degenerate binary stars or binaries made of two white dwarfs. Recent models show that the secondary star in a single degenerate binary will cause bright shock emission in the first hours or days after the explosion while double degenerate explosions are expected to brighten monotonically. We propose to monitor about 100 bright galaxies at $z<0.05$ in the Kepler field to obtain the early light curve of a couple of supernovae. Kepler offers a unique opportunity to observe the early light curves of supernovae in unprecedented detail. No other experiment- past, present, or presently planned- can match the time resolution and continuous monitoring of the Kepler mission. This program is also sensitive to shock breakouts in core collapse supernovae which constrain the physics of the early explosion. We are using the KAIT Supernova Search to monitor these same galaxies on a weekly cadence to quickly alert us of a transient. We have also successfully proposed for spectroscopic follow-up with the Gemini-North 8-m telescope when a supernova is detected. No supernova was seen in Q10 of Cycle~3.

Douglas Gies
Georgia State University

The exquisite accuracy and temporal coverage provided by Kepler has led to the discovery of hundreds of pulsating stars in the Kepler Field of View. Many of these are members of eclipsing binary systems in which a companion star crosses in front of the pulsator each orbit. We have discovered many such pulsators among eclipsing binaries with primary stars for massive than the Sun, and these probably belong to the delta Scuti and gamma Doradus classes of pulsating stars. Many of these are nonradial pulsators in which the flux variations are organized in spatial sectors across the visible hemisphere of the star. Here we propose to use the method of eclipse mapping to determine the degree and azimuthal order of the dominant pulsation mode in four eclipsing binaries. The detailed eclipse changes in the flux recorded by Kepler are closely related to the flux distribution across the occulted portion of the pulsating star, and we will use the new short cadence data to extract the details of the spatial flux variations caused by nonradial pulsations.

Douglas Gies
Georgia State University

The formation of close binary stars requires the extraction of a large fraction of the angular momentum of the original star forming cloud. Theoretical models suggest that most of the angular momentum is deposited in the orbital motion of a distant third star, and there is evidence from ground-based studies that many close binaries do indeed have a tertiary companion. Kepler observations of eclipsing binaries offer us an important opportunity to search for such tertiary stars by measuring the deviations in eclipse times caused by light travel time variations as the binary moves about the triple star system center of mass and by perturbations in the inner orbit caused by the gravitational influence of the third star. We have begun a program of eclipse timings with Kepler that indicates that 16 of 41 (39%) eclipsing binaries have third companions with period of a few years. Here we propose to greatly enlarge the sample in order to determine if this same fraction is found among eclipsing binaries with periods larger than a few days (the typical orbital period of systems in the original sample. The primary advantages of the new survey are an increase the overall sample size by a factor of three, a greatly expanded range of eclipsing binary periods, and much better sensitivity in the detection of long outer periods by leveraging the long time interval between Kepler observations in Cycle 1 and 4. This survey of eclipsing binaries will determine the frequency and character of their low mass companions. These properties will offer important clues about the star formation process and the role played by third stars.

John Gizis
University Of Delaware

We propose to monitor a nearby (17 pc) L dwarf to obtain a year-long time series. The Kepler data, together with supporting multiwavelength observations, will provide a unique dataset to probe the atmospheric properties of dusty brown dwarfs. Both magnetic starspots and clouds are believed to be possible sources of variability in ultracool dwarfs. We will contrain and model the spot/cloud properties and compare to properties of hotter (M dwarf) stars. We will also search for flares, which are believed to be common in L dwarfs even with quiescent chromospheres.

John Bochanski
Villanova University

We propose Kepler long cadence ultra-high precision photometry of 60 carefully selected candidate white dwarf - M dwarf (WDM) binaries not yet observed with Kepler. These suspected close binaries are unresolved point sources (indicative of their proximity) and were identified through multi-band photometry, including griz observations and GALEX NUV detections. There have been no major time-domain studies that have targeted these objects, and the current physical understanding of these systems is very limited. The precision, cadence and long baseline of Kepler observations provide the ideal dataset for conducting the following investigations: 1) Identifying periodic phenomena associated with both components of the binary, including eclipses, rotation/orbital periods, ellipsoidal variations, doppler boosting, and accretion hotspots; 2) quantifying the observable properties due to magnetic fields in the secondary, including starspots and flares; 3) Likely doubling the known number of eclipsing WDM systems and measuring the fundamental properties of both components from eclipse lightcurves and follow-up radial velocity measurements; 4) Detecting and measuring pulsations from the white dwarf primary (e.g., ZZ Ceti stars), and possibly from the M dwarf secondary. Our new observations target early-type M dwarfs (< M4) and complement existing Kepler studies which have focused on later M dwarfs. We will employ ground--based follow-up photometric and spectroscopic observations with guaranteed telescope time of confirmed eclipsing systems and other astrophysically interesting stars. This study will have far-ranging implications on the understanding of these stars and binary star evolution, including post-common envelope and pre-CV stages.

Joyce Guzik
Los Alamos National Security, LLC

In preparation for the potential end of the Kepler mission during Cycle 4, we propose to "fill the gaps" in the Kepler discoveries related to delta Scuti and gamma Doradus stars and their hybrids so that this data will be useful in the future for asteroseismic interpretations. The delta Scuti and gamma Doradus pulsating variables are main-sequence (core hydrogen-burning) stars with masses somewhat larger than the sun (1.2 to 2.5 solar masses). The lower-mass gamma Dor stars are pulsating in nonradial gravity modes with periods of near one day, whereas the delta Sct stars are radial and nonradial p-mode (acoustic mode) pulsators with periods of order two hours. Because of the near one-day periods of gamma Dor stars, it is very difficult to discover and monitor these variables from ground-based photometry or spectroscopy due to the 1 cycle/day alias. We were surprised to learn from the first Kepler data that most of these variables actually show pulsations of both type simultaneously. Theoretical models predict only a small overlap region in the Hertzsprung-Russell diagram where hybrid behavior was expected, due to the different, almost mutually exclusive, driving mechanisms for the two types of pulsation. The Kepler Asteroseismic Science Consortium (KASC) and our Cycle 1, 2, and 3 Guest Observer investigations have been searching for new hybrids and characterizing their pulsation behavior to inform a new explanation for the variety of frequency and amplitude spectra, and compile statistics on the occurrence of pulsators and constant stars. We are proposing GO Cycle 4 observations with several objectives: 1) Obtaining one month of short-cadence (1-minute integrations, SC) data for bright delta Sct and gamma Dor stars that so far have only been observed in long cadence (30-minute integrations, LC) by KASC. The SC data is essential to sort out intrinsic pulsation frequencies from 'reflection' frequencies that may be in the Fourier transform due to undetected frequencies above the LC Nyquist frequency. For these bright stars where it will be possible to obtain ground-based spectroscopic data for further constraints and intensive study, we want to derive an unambiguous intrinsic pulsation frequency set for asteroseismology. 2) Obtaining extended SC time series for several bright KASC hybrid stars that have high frequencies requiring SC data, but will fall on Module 3 or were otherwise deprioritized in the more restricted KASC target list for remaining quarters and Extended Mission planning. It is important to observe these brighter targets that have excellent potential for ground-based followup to optimize signal-to-noise and monitor amplitude and frequency variations. 3) LC monitoring of a number of stars that have been identified as interesting gamma Dor or delta Sct stars in GO Cycle 1 and 2 observing programs to study frequency and amplitude variations and improve signal-to-noise. 4) LC observations for a new sample of stars never monitored before by Kepler, taking advantage of the work of Co-I Kinemuchi on identifying potential variables by difference imaging of eight Kepler full-frame images from Quarter 0, taken during the commissioning phase when the telescope was optimally focused and thermally stable. From Cycle 2 observations, we learned that gamma Dor or delta Sct variability was easily observed even for stars at 15th-16th magnitude and we would like to extend the statistics for fainter objects, as discussed in our Cycle 3 GO proposal. We will likely never have the opportunity after Kepler in this generation of astronomers to discover so many gamm Dor stars due to the 1 cycle/day alias of ground-based observations. We expect that filling in these gaps in the observing will provide a body of data that will be useful for years to come to develop statistics on the frequency of variability, and explaining the variety of frequency spectra, and as input for detailed asteroseismic studies.

Joyce Guzik
Los Alamos National Security, LLC

At visual magnitude 4.5, the F4 main-sequence star theta Cyg (KIC 11918630) is the brightest star that falls on active silicon in the Kepler CCD field of view. Custom aperture observations of theta Cyg requiring 1800 pixels in Quarters 6 (June-Sept. 2010) and 8 (January-March 2011) revealed solar-like oscillations spanning at least 17 radial orders. The brightness of theta Cyg allows for ground-based high-resolution spectroscopy to obtain abundance, rotation, effective temperature and surface gravity constraints. Angular diameter measurements from interferometry combined with HIPPARCOS parallax measurements give excellent constraints on the luminosity and effective temperature. With an effective temperature around 6600 K, theta Cyg falls near the border in the Hertzprung-Russell diagram between the gamma Doradus pulsating variables with gravity-mode pulsations driven by the convective blocking mechanism at the base of the convective envelope, and solar-like oscillators with pulsations driven stochastically by convection at the top of the convective envelope. While no gamma Doradus gravity modes have been observed so far in theta Cyg, possibly because of low-frequency background that may result from granulation, stellar activity, or instrumental effects, a longer time series of observations may reveal such g modes. Finding the first hybrid gamma Dor/solar-like oscillator would be valuable in confirming the pulsation driving mechanism that depends on the convection zone depth, constraining convection and diffusive settling models, and even to inform the solar abundance problem, as the convection zone depth is sensitive to differences in element mixtures. A longer time series of Kepler observations is necessary to make use of the solar-like oscillations, as with only the existing Kepler data, the peaks in the power spectrum are wide as modes are heavily damped (as is true for other well-studied solar-like F stars Procyon and HD 49933), and so the mode identification is ambiguous between modes of degree l = 0, 2 and l =1, 3. A longer time series will also realize the potential to study mode lifetimes and understand why the theory for mode amplitudes and lifetimes for solar-like oscillations in G-type stars does not work as well for F stars, to resolve the rotational splitting in the less damped lower frequency modes to study differential rotation, and use seismic signatures to infer the envelope convection zone base. If gamma Dor g modes are found, these also have potential to constrain the convective core size and core overshoot. A long-enough time series on theta Cyg may allow us to follow changes in the frequencies to discover and study a possible magnetic cycle. We propose a continuous time series of custom aperture observations of theta Cyg for as long as possible (to the end of the Kepler mission and through the Extended Mission). We will carefully process the pixel data to optimize the chance to find g modes, and to study granulation and stellar activity. We will use the combined data to obtain accurate p-mode frequencies, mode identifications, amplitudes, and lifetimes. We will work with a large group of colleagues to obtain constraints from recent spectroscopic and interferometry observations and combine them with the frequency information for stellar modeling and asteroseismology.

Thomas Harrison
New Mexico State University

Analysis of the light curves for the 849 low-mass stars in our Cycle 1 program (Harrison et al. 2012) have lead to the discovery of many dwarf stars that have apparent rotation periods in excess of 90 days. According to theory, such stars should be quite rare. In addition, the active regions on these objects appear to persist for the duration of our Kepler observations (up to 270 d!). We seek additional, year-long, long cadence observations of these targets to both measure their rotation rates, as well as to investigate the longevity of their active regions. In addition to the discovery of the "slow rotators", we have found that low-mass stars often show two unexpected light curve morphologies: "flat minima" and "antipodal". Flat minima light curves require large bands of activity spanning 270 degrees of longitude. Antipodal light curves indicate spots on opposing hemispheres. Both of these types of light curves suggest persistent magnetic field structures that remain largely unaffected by the differential rotation expected to occur in these late-type stars. We seek new long cadence Kepler observations that span Cycle 4 for these objects to explore the formation and evolution of these light curve morphologies. Finally, we have identified 29 targets from our Cycle 1 program that clearly display evidence for differential rotation. Due to the changing spot morphologies on these targets, however, it is difficult to measure their relative differential rotation rates with only a single quarter of data. We request new observations of these targets that span Cycle 4 to allow us to confidently measure their differential rotation rates. Our program requests new data for 242 targets.

Jason Jackiewicz
New Mexico State University

We propose to study the tidal effects that a stellar companion generates on solar-like oscillations of a red giant star in a binary system. The extremely high quality of Kepler data and the asteroseismic analysis techniques recently developed for these types of stars will allow the detection of tidally-modified frequencies for the first time. We will search for the influence of tidal forces as frequency shifts of the spectrum with respect to the unperturbed case, as well as variations of the frequencies with time over the orbital period, for a range of different binary systems. The observations will be modeled primarily using a 3D radiative hydrodynamic code (CO5BOLD) that can simulate the effects of tidal forces in pulsating star models. Synthetic data will be produced to comare to Kepler light curves and asteroseismic measurements. This project could open the door for exciting new studies of binary systems, well-known to be ubiquitous throughout the galaxy. It also takes advantage of the ultra high signal-to-noise of Kepler, necessary for detecting the small variations we expect. Since stars in binaries already provide estimates of a set of stellar parameters, our inferences will be well-constrained and provide unique insights into the effects that tidal forces have on stellar pulstations.

Kenneth Janes
Boston University

The exquisite photometry and continuous viewing capability of the Kepler spacecraft make it possible for the first time to measure directly the rotation periods of stars older than a few hundred million years, by tracking the subtle brightness changes as starspots cross the stellar surface. Two, or possibly three, of the four star clusters in the Kepler field of view will enable a extension of the age/mass/rotation-period calibration to older ages. However, the cluster calibrations will add just two or perhaps three points to the age-period relation, and furthermore, the cooler cluster stars are too faint to be observable with Kepler. To fill in the calibrations and particularly to extend them to the cooler stars, we are planning to observe a selection of common proper motion stellar pairs that cover a wide range of spectral types from late F stars to M dwarf stars. We will assume that the stars in these pairs are coeval, even though initially we may not know their actual ages. The key questions we will address are how the rotations of stars (especially cooler stars) of the same age depend on temperature and how much dispersion there is in the age-rotation relation at a given age.

Christoffer Karoff
Aarhus University

We propose to observe 20 of the brightest, most Sun-like, stars in the Kepler field in short cadence simultaneous with the Kepler mission and from the Nordic Optical Telescope. Astronomers have been making telescopic observations of sunspots since the time of Galileo, gradually building a historical record showing a periodic rise and fall in the number of sunspots every 11 years. We now know that sunspots are regions with an enhanced local magnetic field, so this 11-year cycle actually traces a variation in surface magnetism. Attempts to understand this behavior theoretically often invoke a combination of differential rotation, convection, and meridional flow to modulate the field through a magnetic dynamo (for a recent review see e.g. Charbonneau 2010, Living Rev. Solar Phys., 3). The Kepler mission can provide the observations of stars other than the Sun that are needed in order to take dynamo modelling to the next level, with the ultimate goal of being able to produce dynamo models that can provide us with reliable forecasts of activity in future solar cycles. Although we cannot observe spots on other Sun-like stars directly, these areas of concentrated magnetic field produce strong emission in the calcium spectral lines. The intensity of the emission scales with the amount of non-thermal heating in the chromosphere, making these lines a useful proxy for the strength of, and fractional area covered by, magnetic fields. In this way stellar activity has been monitored in over 111 stars over the last 40 years with the Mount Wilson survey. This survey has revealed that around half of the Sun-like stars show clear periodic cycles, with periods between 2.5 and 25 years (Baliunas et al. 1995, ApJ, 438, 269). Later studies of this and other samples suggest that there are two different kinds of stellar cycles for Sun-like stars - one active and one inactive (Saar & Brandenburg 1999, ApJ, 524, 295), a separation also known as the Vaughan-Preston gap (Vaughan & Preston 1980, PASP, 92, 385). The reason for this bifurcation could be that the dynamo is operating at the top of the near surface convection zone in the active stars whereas it is operating at the base in the inactive stars (Bohm-Vitense, 2007, ApJ, 657, 486). Stellar cycles can also be observed using asteroseismology, as has been shown by helioseismic observations of small frequency shifts of the p-modes (Chaplin et al. 2007, ApJ, 659, 1749) and in amplitude changes of the p-modes (Chaplin et al. 2000, MNRAS, 313, 32). By combining the asteroseismic manifestations of stellar cycles that we can obtain from Kepler with ground-based activity measurements from the Nordic Optical Telescope we will be able to impose hard constraints on the dynamo models, as these models will need to account simultaneously for the variations seen in the calcium emission lines and in the p modes. These constraints can be tightened further by including information from asteroseismology on the interior structure and dynamics of these stars - most importantly the depth and rotation profile of the convection zone (Karoff et al. 2009, MNRAS, 1226). Also, observations of the activity in the Kepler targets will allow us to relate the results from the asteroseismic analysis to various results from stellar activity surveys such as the age-rotation-activity relations (Skumanich 1972, ApJ, 171, 565). The 20 stars we propose to observe as part of the GO proposal have all been observed continuously since quarter 5 and none of them are on module 3. During that last two years we have obtained 6 epochs of ground-based activity measurements from the Nordic Optical Telescope and we intend to continue to observe these stars with the Nordic Optical Telescope in the years to come.

Steven Kawaler
Iowa State University, Ames

The subdwarf B (sdB) stars lie at the extreme blue end (Teff~25,000-35,000K) of the horizontal branch, and are the remnant cores of stars that have experienced the core helium flash while on the RGB. They have extremely thin (and inert) hydrogen shells surrounding a core undergoing helium fusion. How these stars form is currently unknown, though leading scenarios include mass transfer in a binary system. Single-star mechanisms have also been proposed and remain viable given the limitations of observables in these stars. The hot subdwarf star B4 in NGC 6791 is one of a handful of sdB stars known to exist in an old open cluster, and the only cluster sdB known to show nonradial pulsations and photometric variability caused by binarity. Previous Kepler data showed that this star is a rich g-mode pulsator. These modes will be used in the construction of a seismic model for the interior of this star, with additional and critical constraints given by cluster membership and therefore knowledge of its total age, metallicity, and initial mass. Additionally, B4 represents an important laboratory for the study of tidal synchronization in close binary stars. As a close binary, tidal effects should influence the rotational state of the components. Nonradial oscillations provide a measure of its bulk rotation rate. The observed oscillation spectrum shows that the sdB star rotates with a period of about 10 days - much longer than the orbital period of 10 hours. Models suggest that the time scale for synchronization should be comparable with the duration of this phase of the star's evolution, meaning that it is currently being spun up through tidal interaction. Our goals for continued observations for another year are twofold - to monitor short-period nonradial pulsations in this star and increase the S/N to expose additional modes for input into seismic models, and to study longer period variations caused by its binarity. Asteroseismic probes of this star, coupled with the additional constraints of cluster membership and the properties of the binary system, should provide important clues about the formation mechanism of the sdB stars. Given its faintness, the multiperiodic variations (45 to 90 minute periods) and the small amplitude of the pulsations, Kepler is the only instrument able to measure these oscillations to the degree of precision needed for asteroseismic analysis.Our second goal is to extend the high signal-to-noise light curve for analysis of the binary system. High-precision Kepler photometry, coupled with ground-based spectroscopy that we will obtain, can measure the orbital properties of the binary, the mass and radius of the companion, and the distance. With an additional year of photometry of the binary light curve, we can begin to place interesting limits on a tertiary components through timing variations, and to look for orbital evolution caused by tidal coupling. Only an extended, uninterrupted time series can address these issues, and at present Kepler is the only instrument capable of providing the needed data. B4 is a uniquely valuable star: a nonradially pulsating star, in a close binary system, within a cluster.

Sarah Lipscy
Ball Aerospace & Technologies Corporation

Kepler observations have shown that >95% of M stars are variable (Ciardi et al, 2011). The time scales for the variability differ depending on the particulars of the evolutionary phase and evolutionary history of each M star. For this Kepler Guest Observer Proposal, we propose to observe 2 M-giant OH/IR stars not yet observed by Kepler to probe the nature of their variability on timescales of weeks to months. These data will help provide key evidence to understand the timescales of variability which, in turn, may enable us to determine the mechanism driving the variability.

Catherine Lovekin
Los Alamos National Laboratory

Upper main sequence pulsating stars are divided into four basic classes: gamma Doradus, delta Scuti, slowly pulsating B (SPB) and beta Cephei stars. The gamma Doradus and SPB stars are generally thought to be g-mode pulsators, while the delta Scuti and beta Cephei stars are p-mode pulsators. With the increased photometric precision available from space-based missions such as Kepler, many hybrid stars have been discovered, which show either gamma Dor/delta Scuti pulsations or SPB/beta Cephei pulsations. All of these stars, make excellent candidates for analysis using asteroseismology. In particular, the B stars (beta Cephei and SPB stars) provide great potential for determining interior structure. These stars are massive enough to have convective cores, and pulsation frequencies have been shown to be capable of probing the extra mixing around the convective core. Many B stars, particularly among the beta Cephei stars, are rapid rotators, and the effects of rotation also leave an imprint on the frequency spectrum of the star. As a result, asteroseismology can be used to measure the rotation rate in pulsating stars. For a few stars, seismic analysis has even constrained the interior rotation profile of the star. Better constraints on the interior structure will help us better understand the physics of rotation and convection in stars. We propose to observe a sample of 55 stars that have shown variability in a series of 8 full-frame images taken over 34 hours during Quarter 0. We have placed constraints on the sample to focus on the B stars discussed above, but expect the targets will also include A-F stars, probably showing gamma Doradus and/or delta Scuti pulsations, as well as rotating, chemically peculiar, and binary stars. We will classify the stars in the sample according to the origin of the variability, and perform stellar modeling on the main sequence pulsators in the sample. Using 2D techniques, we can include the effects of rotation on the pulsation spectrum in a self-consistent manner, and constrain the mass, age, rotation rate and convective core overshoot for these stars. Asteroseismological techniques are currently the only method capable of constraining all of these properties simultaneously for single stars. Long-cadence data is capable of detecting periods in the B stars and gamma Doradus pulsators, as well as periods longer than 1 hour in the delta Scuti stars. Previous studies of B stars have shown that the frequency spectrum looks very different when observed from space, as more low amplitude and high order frequencies become visible. Observations of this sort are only available with Kepler, and with no similar projects in the planning phase, this may be our last opportunity to observe stars to this level of precision.

Eduardo Martin
University Of Florida, Gainsville

Ultracool dwarfs are numerous in the the solar vicinity. They constitute the low-mass tail of the stellar mass function. The substellar-mass borderline at 75 Jupiter masses is thought to lie at spectral type of M6.5 in the well-known Pleiades cluster. Field dwarfs with spectral type M7 and later include very low-mass stars as well as brown dwarfs. Due to their intrinsic faintness, only 9 very low-mass dwarfs are actually being monitored by the Kepler mission. We propose that 32 additional late-M and L dwarfs are observed during Kepler GO Cycle 4. We have selected these additional dwarfs using multi-wavelength photometric data as well as low-resolution optical spectroscopy for a subset of them. The unique combination of high photometric accuracy and continuous light-curves provided by Kepler can be used to address the following scientific goals: (1) Determination of surface rotational periods for very low-mass stars and brown dwarfs. Stable features in the surface of very low-mass objects, such as long-lived magnetic cool spots or weather patterns such as the red spot on Jupiter, are expected to induce periodic modulation in the light-curves. Periodogram analysis of the Kepler data will yield rotational period for the objects in our sample. (2) Characterize the properties of surface temperature inhomogeneities and their evolution from analysis of continuous light curves of very cool dwarfs. The inhomogeneities in our targets can be due to two kind of features; cool magnetic spots or cloud decks where dust grains are expected to condense. The presence of clouds and their weather-like behaviour can be inferred from the detailed analysis of Kepler light curves. A decrease in the strength of the dominant TiO molecular bands at spectral type M7 and later is a spectroscopic hallmark for the formation of metallic dust condensates in the atmospheres of ultracool dwarfs. Dust grains are thought to condensate into cloud decks that may cover a fraction of the photo-sphere an induce irregular time variable phenomena akin to weather on the atmospheres of planets. (3) Identification of very low-mass eclipsing binaries. So far no eclipsing binaries have been detected with spectral type later than M6. The proposed Kepler observations could detect the first ultracool eclipsing binary, which would be a benchmark for extending the mass-luminosity-spectral type relation to lower masses. The study of eclipsing binaries is much needed to constrain models of very low-mass stars, brown dwarfs and gas giant planets. (4) Characterization of the habitable environment around very low-mass central objects. The habitable regions around late-M and L dwarfs are thought to be tightly wrapped around the central objects. Detailed calculations of the habitable regions around very low-mass stars and brown dwarfs need as input the knowledge about the magnetic activity of these objects. Kepler will provide unprecedented information on the flare frequency and duration of late-M and L dwarfs. The rate of flare events observed in Halpha emission has been observed to increase toward the late-M spectral types with a peak around M8 and a decrease for later types. However, continuous observations of flare events for timescales of weeks and months in these late spectral type objects are sorely missing. We propose to carry out a homogeneous analysis of our 32 targets together with 9 other very low-mass dwarfs already monitored by Kepler. We propose to develop a model to study the surface thermal inhomogeneities of very low-mass dwarfs using Kepler light curves. A custom-made PSF analysis tool will also be developed to improve the photometric accuracy for faint targets. These software tools will be made available to the entire scientific community.

Bernard McNamara
New Mexico State University

We propose to examine 48 B stars in the Kepler field of view that have light curves suggestive of the presence of star-spots. Magnetic fields, presumably associated with these star-spots, are known to be present in a number of # Cephei (# Cep) and Slowly Pulsating B stars (SPBs), but their origin and impact on stellar rotation, pulsations, and element diffusion are poorly understood. Therefore, this proposal addresses two areas of stellar astrophysics that are infrequently studied: magnetism and rotation. This project will address the following questions: How prevalent are spots on B stars, what common morphologies are present in the light curves of these stars, and is spot substructure present? Over what duration are the star-spot amplitudes stable? How many spots are required to match the light curves and what are the spot sizes, locations, and brightnesses? What are the rotation periods of these stars? After subtraction of the star-spot signal, are any pulsation frequencies present that can be used for subsequent asteroseismology analysis? Observations for thirty-eight of our target stars are requested for a full year in the long cadence mode. Short cadence observations to track possible changes in the star-spot substructure are requested for 10 stars, divided into groups of 5 to 7 stars per quarter. This will allow variations to be sought over a 1 year time period.

Joanna Molenda-Zakowicz
University of Wroclaw

Star spots are characteristics of solar-like activity observed in cool stars. They are tracers of magnetic flux tube emergence and can provide information on the different forces acting on the flux tubes during their buoyant rise from the sub-photospheric convective layer. They include information about the photospheric motions, such as the latitudinal drift of spots along the activity cycle, and about the differential rotation which are basic ingredients of the dynamo mechanism for the magnetic field intensification. The convective motions which play a key role in the generation of magnetic fields are also responsible for the excitation of solar-like pulsations. On the other hand, the magnetic field itself quenches the amplitude of those oscillations. Therefore, it is very important to study the trade-off between these two physical phenomena since they are closely related to our ability to derive physical parameters of the solar-like stars. That concerns in particular our ability of deriving the stars' radii and the radii of the planets discovered at them. Active stars in the Kepler field can be best selected on the basis of their coronal emission. Such X-ray-selected star samples shall contain a significant fraction of young stars with an age of a few 100 Myr and also stars as old as about 1 Gyr. We note that such a sample should contain also more evolved stars in binary systems, i.e., the RS CVn variables. Such stars rotate much faster than if they were single and as a consequence are visible in the X-rays. One of the best sources of the information about X-ray stellar sources is the ROSAT All-Sky Survey and the XMM-Newton (X-ray Multi-Mirror Mission - Newton). They can be cross-matched with the Kepler Input Catalog in order to produce the list of X-ray sources in the Kepler field of view. Some of such stars have been already observed with the Kepler instrument and the exquisite quality of the Kepler photometry allowed a detailed analysis of their light curves. The study of KIC 8429280 by Frasca et al. (2011) shows how many fine details of the inner structure of active stars can be derived that way. An interesting point of that study is that the solar-like oscillations are not visible in the power spectrum of the Kepler short-cadence time series of KIC 8429280. That indicates that either the convective zone of this star excites oscillations of tiny amplitude or that the very strong magnetic field suppresses the pulsations. We plan to accomplish a detailed characterization of all the X-ray sources in the Kepler field of view in terms of atmospheric parameters and activity level, and to discuss the issue of the detectability of solar-like oscillations in such stars. Since our targets will also be observed spectroscopically from the ground, we will be able to present a full picture of those issues resulting from our study.

Mike Montgomery
University Of Texas, Austin

We propose to use the nonlinearities present in the light curves of large-amplitude Gamma Doradus and Delta Scuti variables to constrain the depth of their convection zones. The basis of this technique is the strong temeperature dependence of stellar convection zones: relatively small variations in the surface temperature due to pulsation can result in large changes in the size of the convection zone during a pulsation cycle, and this in turn introduces nonlinearities into the light curves. This technique has been successfully applied to pulsating white dwarf stars and should be straightforward to apply to the Gamma Doradus stars since both types of variables are g-mode pulsators. Additionally, we plan to extend this analysis to the high-amplitude Delta Scuti stars (HADS). Since they are p-mode pulsators we will need to include the change in radius in our modeling, although the fact that these stars are dominated by radial modes (l=0) will greatly simplify the analysis. Furthermore, we seek to monitor changes in the convection zones of these objects over multiple epochs. We therefore request continuing long-cadence observations for three Gamma Doradus stars and one month each of short-cadence monitoring of two Delta Scuti stars in the upcoming Kepler observing cycle. For the Gamma Doradus variables there are at present two competing proposed mechanisms for the source of mode driving based on completely different assumptions regarding the physics of convection in these objects; our analysis will help resolve this long-standing question. For the Delta Scuti Stars our analysis will provide important constraints on these difficult to model objects. Finally, we note that our approach is one of only two techniques that can be used to measure the depth of the convection zone of a pulsating star, and it is the only one available for stars such as the Gamma Doradus and Delta Scuti variables. As a result, this investigation will provide important data with which to test the results of hydrodynamical simulations of convection in this part of the HR diagram.

John Monnier
University Of Michigan, Ann Arbor

For Guest Observer Cycle 4, we propose observations of 21 Kepler targets with rapidly changing intensities indicating extreme starspot activity. Many of our targets are suitable for ground-based follow-up and include young solar analogs as well as spotted giants rotating near their break-up velocity. With a well-tested light-curve inversion algorithm, we will model the stellar surfaces in order to measure spot geometry, longevity, and differential rotation. The unique Kepler dataset will allow us to detail how magnetic geometries change on both rotational and long-term timescales, offering unprecedented clues into the nature of the stellar dynamo for active stars and hope to detect long-term magnetic cycles with continued monitoring.

Robert Olling
University of Maryland, College Park

We propose to continue to monitor about 400 galaxies in the Kepler field for light variations at the milli-magnitude (mmag) level to detect previously unknown active galactic nuclei (AGN). Kepler's ability to make measurements at unprecedentedly low amplitudes of variability allows us to to study with extraordinary precision, for a large sample, the correlations with time an hour (long-cadence mode) to about a year. Current results for bright AGNs indicate that the break in the optical power spectrum lies beyond the time scales sampled by a single year of Kepler data (Mushotzky, 2012, private communications). We request a second year of data to be able to pinpoint the break in power law of AGN with low level of variability. The AGN discovered will be followed up with imaging and spectroscopy with UMd guaranteed time on the 4.3 m Discovery Telescope and provide better relationships between black-hole and accretion disk characteristics and variability.

Jerome Orosz
San Diego State University

Kepler's unique combination of high-precision, high duty-cycle, and large sample size enables investigations that are impossible to do otherwise, and thus Kepler is ushering in a new era in stellar astrophysics. Kepler has observed approximately 197,000 stars in total, of which about 160,000 are continuously being observed. Of those, 63,116 are main sequence K and M stars, and 13,161 are brighter than Kp=14.5 mag. However, this sample of K and M stars is incomplete - there are nearly 1000 bright systems in the field of view that Kepler has not, and is not planning to, observe. We propose to complete the Kepler survey of bright (and hence nearby) K and M dwarf stars with this GO proposal. Specifically, we request one Quarter of observations on each of the "missing" 968 stars with Kp <14.5 mag, log g >3.9, and temperatures Teff <5500 K (values are taken from the Kepler Input Catalog "KIC"). We will analyze and catalog these targets based on their light curve morphology, and the number of stars is small enough that we can give each system individual attention. This no-risk proposal is a guaranteed success in that it will certainly reveal many new cases of pulsating stars, variable stars, eclipsing binary stars, and potentially more exotic stellar systems. But most importantly, it completes Kepler's reconnaissance of the bright, main sequence, K and M stars.

Roy Ostensen
Catholic University Leuven

V777 Herculis stars are pulsating white dwarfs of intermediate temperature (Teff ~ 20,000 - 30,000 K) and pure helium atmospheres. They have evolved past the asymptotic giant branch stage, and must have suffered a late thermal pulse that has removed practically all remaining hydrogen from the star. We propose to observe KIC 8626021 in Short Cadence mode for the duration of Cycle 4 of the Kepler Mission, and beyond. This target was identified as a pulsating white dwarf of the rare V777 Her type based on one month of Kepler short cadence data from Q7 by ěstensen et al.(2011 ApJ 736 L39). Recently, an asteroseismic analysis of the target by Bischoff-Kim & ěstensen (2011 ApJ 742 L16) has demonstrated that it is significantly hotter than the temperature indicated by the preliminary spectroscopy, which opens up the prospect of probing the fundamental physics of plasmon neutrino cooling by measuring the period changes in the pulsation periods. V777 Her stars are in themselves very rare objects of which only ~20 are known, but pulsators at the hot edge of the instability strip are exceedingly rare with only a single object firmly established in the literature. Because this star is faint (Kp=18.47), ground based data of sufficient quality and duration is extremely difficult to obtain. Kepler's unwavering gaze, on the other hand, has no problem detecting the pulsations with excellent quality, and we predict that a significant detection of neutrino emission can be made in four years or less.

Peter Papics
Catholic University Leuven

This proposal is a resubmission of our selected Kepler Guest Observer - Cycle 3 proposal entitled "Core overshooting and rotation inside main-sequence B pulsators" (10-KEPLER10-0036) with some minor modifications and additional details included. For a sample of 9 carefully selected B stars (based on the public Q1 data of non-KASC targets, see Debosscher et al., submitted to A&A) we will deduce the core overshooting parameter value from frequency and period spacings (see Degroote et al. 2010, Nature, 464, 259), and check if we can establish a relation between it and the stellar mass. Via the detection of rotational splitting (see Aerts et al. 2003, Science, 300, 1926) - which was not achieved yet from CoRoT data for B stars - we plan to check the internal rotational law of these carefully selected hot massive stars. To have a sufficient frequency resolution, we need at least one year of long cadence data. We have guaranteed access at the 1.2 meter Mercator telescope on La Palma to take high resolution HERMES spectra for the brighter targets simultaneously with the Kepler observations during the entire season in 2011 and 2012 when the field is visible, and we plan to submit proposals for other spectrographs on larger telescopes to extend our coverage. The first spectroscopic measurements already confirmed that the targets are main-sequence stars of spectral type B, with various projected surface rotational velocity values.

Geraldine Peters
University Of Southern California

Kepler observations during Cycles 1 & 2 have revealed a set of short-period eclipsing binaries with Algol-type light curves that display unequal brightness at their quadrature phases. The relative brightness of the quadrature light varies and numerically reverses over a time scale of about a 100-400 days. We call these systems L/T (leading hemisphere/trailing hemisphere) variables. To the best of our knowledge such behavior has never been identified from ground-based photometry. Preliminary analyses of targets in our Cycle 2 program suggest that the L/T behavior is due to a migrating hot spot on the primary star. To study the L/T phenomenon and assess its importance in mass transfer, angular momentum loss, and the evolution of Algols, we propose Kepler observations of 21 L/T systems. We will investigate variability in the size of the hot spot and whether it is always present or episodic and perhaps is correlated with enhanced mass transfer events. The prototype is WX Dra which shows L/T variations of 2-3% of the quadrature flux on a time scale of 1-2 years. Modeling of the light curve reveals that the L/T variability is caused from a migration of a hot spot toward larger phases. One short cadence observation of WX Dra reveals prominent delta Sct-like pulsations on the primary star with a period of 40 min and light amplitude variations of about 2% of its mean quadrature light. All 21 systems will be monitored at the long cadence for the duration of Cycle 4, while one short cadence observation will be secured for each system to investigate its pulsation activity. WX Dra will be observed three times at the short cadence to investigate whether spot location influences the pulsation mode/period. We will determine whether the L/T variations are periodic or episodic. The data will be modeled with a contemporary version of the Wilson-Devinney program. This project will provide important information for theoretical research on Algol binaries as hot spots can drive mass and angular momentum out of the system and influence the evolution of the binary (Van Rensbergen et al. 2008, 2010). Insight on mass transfer dynamics will also be gained.

Ruth Peterson
Astrophysical Advances

We propose long-cadence Kepler observations for 160 targets selected photometrically to be giant or subgiant members of the old, metal-rich open cluster NGC 6791. 130 were observed in Cycle 3, to detect eclipsing binaries among evolved stars. Thirty more will establish the full spatial extent of the cluster. The primary goal is to detect eclipsing binaries suitable for determining the masses of the components, through future ground-based observations of radial velocities. This will constrain comparisons of the cluster color-magnitude diagram at evolved stages, and the influence binaries have on it. We need a large target sample to isolate favorable binaries, as some stars will be non-members, only half of the members will be in binaries, many of these will have merged, and only a few of those remaining are useful. Suitable binary systems should not be triple, and should include a giant and a main-sequence turnoff star so that both components can be detected spectroscopically. The components must not have previously exchanged or lost mass. Binary periods must be one to a few years, the orientation must be nearly edge-on, and the eccentricity will be finite but should not be large. Because giant radii are large, many targets are needed. From this sample we expect to detect roughly a half-dozen binaries from which meaningful masses can be obtained. Kepler is already looking at many targets near the cluster center, where proper motions provide membership information. Our thrust here is the outer regions of the cluster, to increase the binary sample and mitigate against possible binary interactions at high cluster density and large stellar radii. By including dozens of stars farther than 10' from the cluster center, whose g-r vs. g-K colors are consistent with those of cluster members, we can begin to assess the extent to which Galactic interaction has expanded the cluster and/or altered binary distributions. As all are rather bright giants, their light-curve oscillation frequencies should be low enough to be detectable in long-cadence curves of a few months' duration. Follow-up ground-based high-resolution spectra will derive stellar and binary parameters and confirm cluster membership, as well as define the primary velocity curve, the secondary velocity offset, and the system period. This should stringently constrain comparisons of observed color-magnitude diagrams to produce meaningful cluster parameters. Such constraints would have major significance for the derivation of age and metallicity from the broadband colors and integrated spectra of old elliptical galaxies, for which NGC 6791 is a critical resolved template.

Marc Pinsonneault
Ohio State University

We propose a comprehensive program that combines Kepler monitoring of 2034 red giants with ground-based spectroscopy for the entire sample. Kepler data yields information on both stellar non-radial oscillations and rotation periods from modulation of the light curve by star spots. The oscillation frequencies can be used to infer precise surface gravities, radii, and masses for the entire sample, along with diagnostics of evolutionary state (the presence or absence of core helium burning). Internal rotation and surface helium may be obtained for some of the stars. High-resolution IR spectroscopy from the APOGEE project in the 3rd Sloan Digital Sky Survey will provide effective temperatures, radial velocities, and individual abundances for 15 elements. The combination of Kepler and APOGEE permits an unprecedented combination of mass, age, chemistry, and kinematic information for red giants. We will provide a treasury of data on red giants which will serve as a fundamental tool for solving problems in stellar populations, stellar physics, and fields that rely on inferences from either. Our primary stellar population science goals from this are: 1) Anchoring the absolute location of the red giant branch and red clump as a function of mass and composition; 2)Inferring the age of the galactic disk and halo and the timescale for alpha-element enrichment; 3)Mapping rotation as a function of mass, chemical composition, and evolutionary state; 4) Testing models of the formation of the galactic disk; 5) Quantifying the age-metallicity relationship and age differences between the thin disk, thick disk, and halo at the solar circle. The Kepler data also provides key tests of stellar interiors and pulsation physics. Major goals of our program in these areas include: 1) Testing models of mixing and dredge-up on the red giant branch; 2) Testing the validity of scaling relations between mean pulsation properties, mass, and radius across a wide range of abundances and luminosities; 3) Studying stars with unusual pulsational properties; 4) Developing quantifiable diagnostics of evolutionary state and core properties; 5) Quantifying the scientific impact of additional time series data for existing targets. To answer these science goals we have designed a sample including both new targets and continued monitoring of a subset of the publicly released red giant sample. Our new targets are primarily luminous giants under-represented in the current Kepler sample. We have also used Washington photometry to identify rare metal-poor giants. Because monitoring of the publicly released red giant sample is not guaranteed, we identified key stars where additional Kepler data is crucial. This includes open cluster members, giants with detected star spot signatures, and stars with unusual pulsational properties. We have also defined a grid of first ascent and red clump giants that will be a fundamental resource for future population studies. We have a strong and multi-faceted team capable of addressing these ambitious goals. Team members have extensive experience in analyzing Kepler data to infer pulsation properties and rotation periods. The APOGEE spectra will be reduced by an automated pipeline that will be in operation by the time of the proposed Kepler observations. Other team members have expertise in stellar interiors, stellar evolution, models of galactic formation, and studies of chemical evolution. With our combined expertise we will provide a comprehensive treasury of public data. The large majority of the work will be funded through other sources. For this program we request 1 year of funding for a graduate student whose dissertation is related to the proposal. We also request funds for all members of the research team to attend the annual Kepler Asteroseismology Science Consortium meeting in 2013 and support for publications.

Elisa Quintana
SETI Institute

M dwarfs are known to exhibit powerful flares due to magnetic reconnection in their atmospheres on timescales from minutes to hours. A previous study of Kepler's Q1 data by Walkowicz et al. (2010) has shown that ~50% of M dwarfs produce flares compared to ~10% in K dwarfs. We propose to observe a set of previously unobserved M dwarfs in the Kepler field-of-view at long (~30 min) cadence to search for and characterize flares. In addition, we propose to observe a small subset of M dwarfs that are known to flare frequently and with short durations to be sampled at short (~1 min) cadence in order to study the fine structure of these flares. We plan to develop a new detection algorithm that will allow us to detect and measure frequencies, durations, and energies of M dwarf flares with this new data as well as with all Kepler data that will be publicly available at that time. This will allow us to examine possible correlations of flares with stellar properties and variability. In addition to increasing our knowledge of M dwarf radiation environments, these results have important implications on exoplanetary habitability.

Mike Reed
Missouri State University

We propose to observe two candidate g-mode subdwarf B (sdB) pulsators in the old open cluster NGC 6791. Using period spacings and multiplets, we will identify pulsation modes. Their memberships within the cluster will also give us their age, metallicity, distance, and constrain their progenitor mass. These properties will directly test the latest generation of structural models. One g-mode sdB pulsator has already been discovered within this cluster by Kepler, so we can expect to find several more, which can be used to compare and contrast with each other to discern additional internal properties, such as stratification caused by diffusion. As sdB stars represent the exposed cores of most horizontal branch stars, recently verified by means of Kepler observations have linked them to cores of clump red giants via period spacings, what we learn about sdB stars translates directly to the cores of most horizontal branch stars. Only Kepler data can provide the extended, uninterrupted time-series data required to detect and fully resolve the pulsation spectrum. These stars are faint at Kp=16.2 and 18.1, Kepler SC data will yield detection limits near 0.06 and 0.12 ppt with a year of photometry which should reveal rich pulsation spectra with tens of periodicities each. These stars have received SC Q11 DDT time which will be used to verify they are pulsators and that the pixel masks used are optimal.

Steven Saar
Smithsonian Institution/Smithsonian Astrophysical Observatory

We propose to observe two candidate g-mode subdwarf B (sdB) pulsators in the old open cluster NGC 6791. Using period spacings and multiplets, we will identify pulsation modes. Their memberships within the cluster will also give us their age, metallicity, distance, and constrain their progenitor mass. These properties will directly test the latest generation of structural models. One g-mode sdB pulsator has already been discovered within this cluster by Kepler, so we can expect to find several more, which can be used to compare and contrast with each other to discern additional internal properties, such as stratification caused by diffusion. As sdB stars represent the exposed cores of most horizontal branch stars, recently verified by means of Kepler observations have linked them to cores of clump red giants via period spacings, what we learn about sdB stars translates directly to the cores of most horizontal branch stars. Only Kepler data can provide the extended, uninterrupted time-series data required to detect and fully resolve the pulsation spectrum. These stars are faint at Kp=16.2 and 18.1, Kepler SC data will yield detection limits near 0.06 and 0.12 ppt with a year of photometry which should reveal rich pulsation spectra with tens of periodicities each. These stars have received SC Q11 DDT time which will be used to verify they are pulsators and that the pixel masks used are optimal.

Eric Sandquist
San Diego State University

Age is difficult to measure extremely precisely for stars other than the Sun. In the field being observed by Kepler, the stars of the open clusters NGC 6791, NGC 6811, NGC 6819, and NGC 6866 are the ones that can be most precisely age-dated. However, different methods provide ages that differ significantly. We propose an effort to bring methods of stellar age determination into agreement through the use of Kepler data for all of these star clusters. Here we focus on the use of masses and sizes measured from weakly-interacting eclipsing binary star systems. Massive stars run out of hydrogen fuel at their centers before less massive ones, and start to change rapidly in size - for such rapidly evolving stars, measurements of both mass and radius that are precise to 1% can lead to ages precise to 10% or better. Further, mass and radius measurements are conceptually simple to derive from observations, and avoid complicating effects like distance and reddening uncertainties. High precision age measurements from this and other methods will make these star clusters important testbeds for stellar populations in galaxies.

David Soderblom
Space Telescope Science Institute

We have found G stars - both on the main sequence and evolved - in the Kepler data releases that exhibit dramatic flares, with energies of as much as 100,000 times those seen in the largest solar flares. These flaring stars are worth examining in much greater detail, both to understand better the physics of flaring, and to understand why these particular stars exhibit this extraordinary behavior and what that may mean for the nearby environments of these stars (and perhaps for the Sun). If they are, in fact, the youngest stars in the Kepler sample, then these flares are putting energies into their surrounding environments at a critical phase in planet formation. However, we believe for several reasons that these stars are not simply the youngest stars in the Kepler sample and are likely to be older stars. If that is true then we are witnessing solar-type stars exhibit behavior not ever seen before, and there are important implications. This proposal has been written to ensure continued observation of the flaring stars, to ensure access to those data, and to obtain one-minute cadence observations of a subset of the flaring stars in order to derive precise physical parameters for these extraordinary objects and to better study the flares themselves. That can then permit gaining a fuller understanding of the context of the extraordinary flaring behavior.

Jennifer Sokoloski
Columbia University

Previous Kepler observations of the symbiotic binary StHA~169, in which a white dwarf accretes from a red-giant companion, revealed an unexpected modulation in its optical flux with a period of around 40 days. The goal of the proposed research is to use additional Kepler short- and long-cadence observations to determine the origin of this modulation. We will test possible explanations such as: 1) the existence of some structure at the outer edge of a large accretion disk; 2) a modulation of the flow through the disk producing a variation in the luminosity of the burning shell on the surface of the white dwarf; 3) pulsation of the red giant; and 4) the presence of a third body in the system. The two challenges for interpreting this modulation are its period and the expectation that the accretion disk produces much less optical emission than the red giant and the surrounding nebula. At 40 days, the period is too short to be due to orbital motion of the binary or rotation of the red giant. It is also unusually short for a red-giant pulsation. Although the period of the oscillation could reasonably be tied to a dynamical or viscous time scale at the outer edge of a large accretion disk, the lack of rapid stochastic variations, or "flickering", from this source on a time scale of minutes suggests that emission directly from the disk does not contribute significantly to the optical light. So, an origin for the modulation in an accretion disk also seems problematic. And to add to the mystery, the pulse profile varies and is often double-humped. To crack this problem, we will combine Kepler monitoring with ground-based photometry and optical spectroscopy throughout several cycles of the oscillation. We also request one month of short-cadence observations to confirm the continued absence of disk flickering. Determining whether the oscillation is dominated by red or blue light will reveal whether it is associated with the red giant or the accreting white dwarf, and pinning spectroscopic changes to each phase of the oscillation will provide evidence for the underlying physics. Although spectroscopy and multi-color photometry require ground-based observations, we need Kepler data to place these observations in the context of the 40-day modulation. Furthermore, increasing the length of the Kepler light curve will give improved frequency resolution to the power spectrum, which is needed to distinguish between models. In summary, explaining the cause of the optical brightness oscillation from StHA 169 could be relevant for understanding the nature of the accretion processes in wide binaries and/or the structure of a Roche-lobe filling red giant. This research program could thus turn a very small allocation of Kepler pixel resources into a finding with broad implications.

Jennifer Sokoloski
Columbia University

The proposed Kepler observations aim to determine the degree to which the physics of white-dwarf accretion disks is the same as that of neutron-star and black-hole disks in X-ray binaries. In particular, we seek to answer the question: does the pattern of brightness variations from a white-dwarf accretion disk change in the same way as that of X-ray binaries when the disks make an extreme change of state? Of all the sources with accretion disks and jets, the comparison among white dwarfs, neutron stars, and stellar-mass black holes is especially illuminating. Although all these compact objects have similar masses, general relativity is needed to describe the trajectories of matter and light in X-ray binaries, whereas in accreting white dwarfs, it is not. So, the juxtaposition of the timing behavior of these systems provides a way to identify both the fundamental underpinnings of disk accretion and the effects of general relativity. To achieve our scientific goal, we will perform short-cadence observations of CH Cyg with Kepler throughout Cycle 4. CH Cyg is a symbiotic star that contains a white dwarf accreting from a red-giant companion. During the 12 months of Cycle 4, we expect CH Cyg to be in a high state, in which the disk is luminous. Prior Kepler short-cadence observations (during Cycles 2 and 3) have already characterized the rapid variations from CH Cyg in the low state; these previous Kepler observations revealed never-before-seen quasi-periodic oscillations (QPOs) and a break in the power density spectrum. If CH Cyg is truly analogous to an X-ray binary, the QPO should shift to higher frequencies in the high state, and the break should shift to lower frequencies if, for example, the geometrical height of the inner disk decreases. CH Cyg is the ideal target for this study because it produces bipolar jets as in X-ray binaries, its orbital period is so long that orbital motion will not interfere with the detection of brightness fluctuations from the disk, and the disk is large enough that any features in the power density spectrum on time scales of minutes to days will reflect dynamical, viscous, or thermal time scales rather than the size of the disk. CH Cyg is also the only source of its type --- an accretion-powered symbiotic star --- in the Kepler field of view, and because it is a dedicated-mask target, the proposed observations do not count against the short-cadence pixel budget. If our Kepler observations confirm the hypothesis that the accretion disks in symbiotic stars and X-ray binaries have the same type of flux variations, there will be far-reaching implications. 1) We will have confirmed the suggestion that the physics behind the features in the power density spectrum must be the same for white dwarfs, neutron stars, and black holes. 2) Models for the QPOs in X-ray binaries that invoke general relativity, and the possibility of using the features in the power spectrum to probe strong gravity, will be called into question. 3) The more than 2 decades of research on X-ray binary variability will become relevant to accreting white dwarfs, and copious research on cataclysmic-variable disks will become relevant to X-ray binaries. Due to the combination of its sensitivity and its capacity for long-duration observations, Kepler is the only instrument that can carry out this project.

Susan Thompson
SETI Institute

Heartbeat stars are a new class of highly eccentric binary systems characterized by a brightening that occurs as the system passes through periastron. The varied shapes of the brightening reveal the orientation and eccentricity of the binary's orbit. Our goal is to measure the tidal evolution of these binary systems and to analyze the stellar components with asteroseismology. Such highly eccentric systems are hard to explain considering the theorized circularisation timescales of radiative stars. These systems are likely still evolving and we plan to measure their evolution by directly measuring the precession of the orbit caused by either the density distribution of the binary components or by a third body. We will also use the observed arrival time of the Heartbeat signal to constrain the presence of a possible third body. The dynamic tidal forces also induce pulsations the Heartbeat stars. Many of our systems lie in or close to the Delta Scuti instability strip. We can combine harmonically driven g-mode pulsations with intrinsic p-mode Delta Scuti pulsations to improve our mode identification and probe both the core and surface of these stars with asteroseismology. The low amplitude variations of these systems and the required timebase needed to accurately measure the pulsations and orbital evolution make Kepler the ideal instrument to accomplish our goals.

Andrew Tkachenko
Catholic University of Leuven

V380 Cyg is the bright double-lined spectroscopic eclipsing binary which properties make it an important "astrophysical laboratory" for studying the structure and evolution of massive stars. V380 Cyg consists of an evolved, more massive primary and a main-sequence secondary stars. The interpretation of the star's properties is problematic in the sense that stellar models are unable to explain the data, unless an extreme value of about 0.6 (in local pressure scale height) is adopted for the convective core overshooting parameter. The ultimate goal of this proposal is to gather sufficient Kepler data and perform an in-depth asteroseismic analysis of this important binary star system. This goal cannot be achieved by any other instrument than the currently operational Kepler space mission. Our recent investigations (Tkachenko et al. 2012) show that the application of the state-of-the-art codes to the high-quality photometric data gathered by the Kepler satellite by means of a specifically defined mask for the V380 Cyg is capable of providing a residual light curve dominated by stellar oscillations. We succeeded to detect several frequencies in the residual light curve, among which exact integer multiples of the orbital frequency. Several more frequencies are hinted at but they do not formally fulfill usually adopted significance criteria. With this proposal, we request more Kepler data to 1) detect more oscillation frequencies and to decide on the significance of the orbital frequency multiples, and 2) to prewhiten the original data with stellar oscillations signal in order to improve the orbital solution and be able to perform seismic modeling based on the residual light curve. The main reason we request one more year of observations (should the mission be not extended, six months of observations would also lead to a better frequency precision than we have now), is that we need a sufficiently long timebase to 1) better resolve the gravity mode frequencies and evaluate their stochastic nature; 2) check for the presence of low-order and medium-order pressure modes; 3) decide on the reliability of the oscillations with exact integer multiples of the orbital frequency which are presently not formally significant with the Kepler data at hand while we anticipate the important result that they are tidally induced oscillations. In the case of positive confirmation of this anticipated result, V380 Cyg will be the first high mass binary where tidally triggered oscillation are observed.

Ann Wehrle
Space Science Institute

We propose to increase by 50% the time baseline of our approved Cycles 2+3 programs to search for variability in four flat spectrum radio quasars (blazars) and one powerful radio galaxy, Cygnus A, on timescales comparable to the light crossing time of the accretion disk (AD) around the central supermassive black hole (SMBH) or the base of the relativistic jet. When the quasars are quiescent, a quasi-periodic light curve indicates an AD origin, and provides a way to estimate the mass of the SMBH. When the quasars are active, long-lived quasi-periodic oscillations (QPOs) are very probably from helical features in the jets; if several different short-lived QPOs are seen in one quasar, then the emission is probably coming from turbulence behind a shock. When we instead see aperiodic variations during a faint state, any high and low frequency breaks in the power spectral density (PSD) yield the inner and outer edges of ADs, hence the BH mass. Breaks in the PSD also could yield physical scales in the relativistic jet. Kepler is ideally suited to the necessary measurements by delivering highly stable photometry continuously on timescales from minutes to days. By adding a third year of data, we will: see more of the quasars' faint quiescent states, thus measuring the duration and occurrence rate of QPO-emitting blobs in the AD; use the better SNR in the PSD to improve our ability to detect the inner and outer edges of the AD; and reduce the error on any SMBH mass estimates by 20% compared to Cycles 2+3. For bright states, we will observe: long-timescale QPO-producing helical features in the jet; short-timescale QPO-emitting blobs near shocks; for aperiodic signals, we could detect twice as large physical scales in the jet, and use the better SNR to reduce error bars on the smallest strong structures in the jet by 20% compared to Cycles 2+3. We have fitted PSDs to our Cycle 2 long-cadence data on radio-loud quasars, and find a power-law slope alpha ~ -2.0, consistent with the variability originating in turbulence behind a shock. These preliminary values are flatter than those in four low-redshift X-ray selected AGN reported by Mushotzky et al. (2011); the intriguing differences in PSDs may be a result of the differences in AGN luminosity or type.

D. Winget
University Of Texas, Austin

We propose to observe and analyze KIC 4552982, so far the only known pulsating DA (hydrogen-atmosphere) white dwarf in the Kepler mission field. The target was identified as a DAV using ground-based data (Hermes et al. 2011 ApJ 741 L16), and the target has been observed through KASC since Q11. Extended Kepler observations of KIC 4552982 could yield the best light curve, to-date, of any pulsating white dwarf, allowing us to directly study the interior of an evolved object representative of the fate of the majority of stars in our Galaxy. We expect to perform precision asteroseismology, explore low-amplitude modes in a search for non-linearities and perhaps l=3 modes, and watch the observed modes evolve in amplitude and phase on new timescales inaccessible from the ground. We will use this unique space-based Kepler data set to leverage our understanding of the entire class of more than 150 known DAV stars.

Matthew Wood
Florida Institute Of Technology

Cataclysmic variables provide the cleanest available natural laboratories to investigate the physical behavior of accretion. The timing capabilities and sensitivity of Kepler are well matched to the timescales and amplitude of accretion variability in these sources. This combination provides an unprecedented opportunity to test and refine the paradigms of stellar accretion with high-precision, uniform data containing no diurnal or seasonal gaps. We propose a multi-faceted observational and modeling program that puts our current understanding of accretion to the test and has the potential to measure the spatial structure of model-dependent disk parameters. Kepler observations of cataclysmic variables will impact profoundly our understanding of accretion dynamics and the nature of viscosity in the broader astrophysical contxt. Our proposed observations will provide an outstanding astrophysical legacy for the Kepler mission archive.

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