Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2025 July 31

Supernova 2025rbs in NGC 7331
Image Credit: Ben Godson (University of Warwick)

Explanation: A long time ago in a galaxy 50 million light-years away, a star exploded. Light from that supernova was first detected by telescopes on planet Earth on July 14th though, and the extragalactic transient is now known to astronomers as supernova 2025rbs. Presently the brightest supernova in planet Earth's sky, 2025rbs is a Type Ia supernova, likely caused by the thermonuclear detonation of a white dwarf star that accreted material from a companion in a binary star system. Type Ia supernovae are used as standard candles to establish the distance scale of the universe. The host galaxy of 2025rbs is NGC 7331. Itself a bright spiral galaxy in the northern constellation Pegasus, NGC 7331 is often touted as an analogue to our own Milky Way.

Tomorrow's picture: pixels in space

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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