Supernova 1993J in Spiral Galaxy M81
This Hubble Space Telescope photo composite shows the location of supernova 1993J inside the majestic spiral galaxy M81. Though astronomers saw the star explode as a supernova 21 years ago, the glow of that explosion is still present, as seen in the inset image. The supernova has faded to the point where astronomers are confident that they have picked up the ultraviolet glow of a very hot companion star. This is the first time astronomers have been able to put constraints on the properties of the companion star in this unusual class of supernova called Type IIb. Hubble observations in ultraviolet light confirm the theory that the explosion originated in a double-star system where one star fueled the mass-loss from the aging primary star.
NASA, ESA, A. Zezas (CfA), and A. Filippenko (UC Berkeley);
Acknowledgment: Hubble Heritage Team (STScI/AURA);
Science: NASA, ESA, and O. Fox (University of California, Berkeley), A. Bostroem (STScI), S. Van Dyk (Caltech), A. Filippenko (University of California, Berkeley), C. Fransson (Stockholm University), T. Matheson (NOAO), S. Cenko (University of California, Berkeley, and NASA/GSFC), P. Chandra (National Center for Radio Astrophysics/Pune University, India), V. Dwarkadas (University of Chicago), W. Li and A. Parker (University of California, Berkeley), and N. Smith (Steward Observatory)