Nova (Encyclopedia of Science)
The word nova, Latin for "new," was assigned by ancient astronomers to any bright star that suddenly appeared in the sky. A nova occurs when
one member of a binary star system temporarily becomes brighter. Most often the brighter star is a shrunken white dwarf, the cooling, shrunken core remaining after a medium-sized star (like our sun) ceases to burn. Its partner is a large star, such as a red giant, a medium-sized star in a late stage of its evolution, expanding and cooling.
As the companion star expands, it loses some of its matterostly hydrogeno the strong gravitational pull of the white dwarf. After a time, enough matter collects in a thin, dense, hot layer on the surface of the white dwarf to initiate nuclear fusion reactions. The hydrogen on the white dwarf's surface burns away, and while it does so, the white dwarf glows brightly. This is a nova. After reaching its peak brightness, it slowly fades over a period of days or weeks....
(The entire section is 425 words.)
Want to Read More?
Subscribe now to read the rest of this article. Plus get complete access to 30,000+ study guides!