| 释义 |
‖ nova|ˈnəʊvə|
Pl. novæ |ˈnəʊviː|.
[L. nova, fem. sing. of novus new.]
†1. (See quot.) Obs. rare—0.
1688Holme Armoury iii. xxii. (Roxb.) 274/1 Sorts of Tobacco: Pig taile, is a very small wreath or roll tobacco..: Nova, the thickest wreath.
2. Astr. A new star or nebula. In mod. use, a star that suddenly increases in brightness by several magnitudes and then, after a period of maximum brightness lasting from a few days to several years, decreases to its former brightness over a much longer period.
Now distinguished from a supernova.
1877G. F. Chambers Astron. 918 Nova; a word introduced by Sir J. Herschel to signify a star or nebula not previously recorded. 1899Daily News 22 Apr. 8/6 The appearance of a Nova was recorded on the plates... The appearances of Novæ have given rise to many theories as to their origin. 1927H. N. Russell et al. Astronomy II. xxii. 777 The brightest stars ever recorded have been novæ. Nova B Cassiopeiæ, known as ‘Tycho's star’, which appeared in November, 1572, was for some days as bright as Venus at her best (visible in the daytime), and then gradually waned. 1939Nature 15 July 122/2 Some of these extra⁓galactic novæ have a brightness equal to nearly 100 million suns... In 1934 Baade and Zwicky suggested that these extremely bright objects were not ordinary novæ, but presented a class by themselves—the class of super⁓novæ. 1955Sci. News Let. 9 July 31/1 Because of a sudden break-down of the normally stable energy conditions in its interior, a nova abruptly flares up to thousands of times its normal brightness, so that a star never before visible from the earth bursts into brilliance. 1956R. A. Lyttleton Mod. Universe v. 167 Every year on the average about a score of stars within our own galaxy undergo this catastrophic development and become what are termed novae. 1968Times 2 Dec. 17/2 Most of the X-ray sources are located in the Milky Way and some of them have been identified with old novae—stars that flared brightly a long time ago and are now fading. |