'Oddball supernova' appears strangely cool before exploding

Astronomers examined a massive star two-and-a-half years before it exploded into a supernova. At the end of their lives, cool, yellow stars are typically shrouded in hydrogen, which conceals the star's hot, blue interior. But this yellow star, located 35 million light-years from Earth in the Virgo galaxy cluster, was mysteriously lacking this crucial hydrogen layer at the time of its explosion.

from Latest Science News -- ScienceDaily https://www.sciencedaily.com/releases/2021/05/210505094437.htm