White dwarf
A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf’s faint luminosity comes from the emission of stored thermal energy; no fusion takes place in a white dwarf. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun.
About White dwarf in brief
A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf’s faint luminosity comes from the emission of stored thermal energy; no fusion takes place in a white dwarf. The nearest known white dwarf is Sirius B, at 8. 6 light years away. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun. The unusual faintness of white dwarFS was first recognized in 1910. The first white dwarf discovered was in the triple star system of 40 Eridani, which contains the relatively bright main sequence star 40Eridani A and the main sequence red dwarf 40Eridani C. In 1939, Edward C. Pickering, a friend of Russell’s, volunteered to have the spectra observed for all the stars he had observed in the stellar parallax. In 1910, Henry Norris Russell, Edward Charles Pickering and Williamina Fleming discovered that, despite being a dim star, 40 Eriridani B was type A, or white dwarf type A. In 1940, Russell looked back on the discovery: 1I visiting visiting Prof. Edward Pickering at Cambridge Observatory, I asked about certain faint stars, and he sent a note to the office saying that he had noticed them all. Characteristically, he came up with a list of stars that all were of very faint absolute magnitude of spectral class M. In particular, he mentioned in particular 40 Erridani B, which came up on the list, and I said that I had observed all of them in particular, including this particular star, which had not been observed in particular before.
This led to the discovery that all of the stars of this class were faint absolute class were white dwarf class M, class A, class B, class C, class D, class E, class F, class G, class H, class K, class L, and class H. The name white dwarf was coined by Willem Luyten in 1922. White dwarfs are the final evolutionary state of stars whose mass is not high enough to become a neutron star. This includes over 97% of the other stars in the Milky Way. The physics of degeneracy yields a maximum mass for a non-rotatingwhite dwarf, the Chandrasekhar limit. A carbon–oxygen white dwarf that approaches this mass limit, typically by mass transfer from a companion star, may explode as a type Ia supernova via a process known as carbon detonation; SN 1006 is thought to have been a famous example. The oldest white dwarf still radiate at temperatures of a few thousand kelvins. The star’s low temperature means it will no longer emit significant heat or light, and it will become a cold black dwarf. Because the length of time it takes for awhite dwarf to reach this state is calculated to be longer than the current age of the universe, it is thought that no black dwarfs yet exist.
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This page is based on the article White dwarf published in Wikipedia (as of Dec. 06, 2020) and was automatically summarized using artificial intelligence.
