Free Astronomy Magazine September-October 2022

42 ASTRO PUBLISHING Pre-supernova hydrogen loss: the companion star is the culprit N ASA’s Hubble Space Telescope has uncovered a witness at the scene of a star’s explo- sive death: a companion star previously hidden in the glare of its partner’s supernova. The discovery is a first for a particular type of super- nova — one in which the star was stripped of its entire outer gas enve- lope before exploding. The finding provides cru- cial insight into the bi- nary nature of massive stars, as well as the po- tential prequel to the ulti- mate merger of the com- panion stars that would rat- tle across the universe as gravitational waves, ripples in the fabric of spacetime itself. by NASA/ESA Bethany Downer SEPTEMBER-OCTOBER 2022