You searched for: “novae”
nova (s), novae (pl)
1. A faint star that suddenly increases in brightness by a factor of 10,000 or more, remains bright for a few days, and then fades away and is not seen again for very many years, if at all.

Novae (plural of nova) are believed to occur in close binary star systems, where gas from one star flows to a companion white dwarf. Such stars which are similar to those appearing in our galaxy have also been observed in other galaxies.

2. The sudden increase in brightness of a star, probably as a result of its interaction with another, very close, star forming a binary system.

The brightness increase is due to the blowing off of a large amount of hot hydrogen gas from the star's surface, the star probably being a white dwarf.

Stars are generally regarded as being unchanging on a human time scale, so the appearance of a newly visible star, or nova, is unusual.

Generally novae brighten suddenly within weeks or days, fade drastically during the following few weeks, then continue to fade more gradually for several years.

This entry is located in the following unit: Astronomy and related astronomical terms (page 17)