Bright supernova discovered in K2's ongoing Campaign 16

News article posted on by Geert Barentsen

The ASAS-SN survey reports the discovery of a bright supernova (V=15) in a nearby galaxy that is currently being monitored by Kepler as part of its ongoing K2 Campaign 16. The event is named ASASSN-18bt (AT 2018oh) and is located at 09:06:39.6 +19:20:17.5 in the galaxy UGC 4780.

The initial spectroscopic follow-up indicates that the event is a Type Ia supernova which is still rising and is several days away from reaching its maximum brightness. We encourage the community to continue to coordinate the follow-up of this unique event via the K2 Supernova Experiment Google Group.

This event is expected to yield the highest-precision lightcurve ever obtained for a supernova. Kepler is providing a continuous 30-minute cadence view of the event from December 7th through February 25th, i.e. starting 2 months before and ending 3 weeks after the explosion.

Figure: spectrum of ASASSN-18bt (AT 2018oh) taken by the Hobby-Eberly Telescope at McDonald Observatory on February 5th. The red line shows a Type Ia reference template. (Image Credit: Jozsef Vinko.)
C16 SN2018oh spectrum