Astronomy Picture of the Day

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

December 27, 1995

Nova Cygni 1992
Credit: NASA, ESA, HST, F. Paresce, R. Jedrzejewski (STScI)

Explanation: In 1992 a tremendous explosion occurred in the constellation of Cygnus. Dubbed Nova Cygni 1992, this event most probably occurred in an accretion disk binary system. Astronomers hypothesize that this system's white dwarf had so much gas dumped onto it's surface that conditions became ripe for nuclear fusion. The resulting thermonuclear detonation blasted much of the surrounding gas into an expanding shell. The Hubble Space Telescope photographed this expanding shell in 1994. Nova Cygni 1992 was the brightest nova in recent history - at its brightest it could be seen without a telescope. It was observed in every part of the electromagnetic spectrum.

Tomorrow's picture: NGC 6240: When Galaxies Collide

Authors & editors: Robert Nemiroff (GMU) & Jerry Bonnell (USRA).
NASA Technical Rep.: Sherri Calvo. Specific rights apply.
A service of: LHEA at NASA/ GSFC