https://amp.space.com/42640-kepler-telescope-captures-early-stages-supernova.html

https://www.nasa.gov/feature/ames/kepler-s-supernova-experiment-captures-first-moments-of-a-dying-star

Kepler space telescope is dead, but before it died.

It’s captured the early stages of a Type 1a standard candle supernova that’s very peculiar indeed.

Astronomers detected the bright light of a supernova called SN 2018oh on Feb. 4, 2018. SN 2018oh resides in the spiral galaxy UGC 4780, in the Cancer constellation. It is classified as a Type Ia supernova, which typically brightens over the course of three weeks before gradually fading away.

However, this supernova, which Kepler observed (unprecedented) only a few days after the initial explosion, brightened about three times faster than a typical supernova before reaching peak brightness. Data from the ground-based telescopes revealed a blue hue, indicating the supernova is extremely hot.

For nearly a decade, scientists have been in search of a signal of a supernova similar to this one. Because Kepler was already staring at this patch of sky before the supernova went off, it was able to detect its early signals and measure it continuously for weeks.

The scenarios giving rise to Type Ia supernovae have been long-debated. So far, most evidence points to the merging of two white dwarfs, the compact corpses of stars, as the source of these explosions. Yet theoretical models have held out the possibility of an alternative scenario, in which a single degenerate white dwarf siphons off so much material from its companion star that it can no longer sustain its own weight and blows up. This latest evidence supports the second scenario.

The team of astronomers detected more than 40 supernova candidates during this experiment with Kepler, including several others that are also proving scientifically interesting.