Pulsating White Dwarf

A pulsating white dwarf is a white dwarf star whose luminosity varies due to non-radial gravity wave pulsations within itself. Known types of pulsating white dwarfs include DAV, or ZZ Ceti, stars, with hydrogen-dominated atmospheres and the spectral type DA, pp. 891, 895; DBV, or V777 Her, stars, with helium-dominated atmospheres and the spectral type DB, p. 3525; and GW Vir stars, with atmospheres dominated by helium, carbon, and oxygen, and the spectral type PG 1159. (Some authors also include non-PG 1159 stars in the class of GW Vir stars.) GW Vir stars may be subdivided into DOV and PNNV stars;, §1.1, 1.2; they are not, strictly speaking, white dwarfs but pre-white dwarfs which have not yet reached the white dwarf region on the Hertzsprung-Russell diagram., § 1.1; A subtype of DQV stars, with carbon-dominated atmospheres, has also been proposed., and in May 2012, the first extremely low mass variable (ELMV) white dwarf was reported.

These variables all exhibit small (1%–30%) variations in light output, arising from a superposition of vibrational modes with periods of hundreds to thousands of seconds. Observation of these variations gives asteroseismological evidence about the interiors of white dwarfs.

Types of pulsating white dwarf, §1.1, 1.2;
DAV (GCVS: ZZA) DA spectral type, having only hydrogen absorption lines in its spectrum
DBV (GCVS: ZZB) DB spectral type, having only helium absorption lines in its spectrum
GW Vir (GCVS: ZZO) Atmosphere mostly C, He and O;
may be divided into DOV and PNNV stars
DQV DQ spectral type; hot, carbon-dominated atmosphere
ELMV DA spectral type;

Read more about Pulsating White Dwarf:  DAV Stars, DBV Stars, GW Vir Stars, DQV Stars, See Also

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