GD 358 explained

GD 358 is a variable white dwarf star of the DBV type. Like other pulsating white dwarfs, its variability arises from non-radial gravity wave pulsations within the star itself.^[1] GD 358 was discovered during the 1958 - 1970 Lowell Observatory survey for high proper motion stars in the Northern Hemisphere.^[2] Although it did not have high proper motion, it was noticed that it was a very blue star, and hence might be a white dwarf.^[3] Greenstein confirmed this in 1969.^[4]

In 1968, Arlo U. Landolt discovered the first intrinsically variable white dwarf when he found that HL Tau 76 varied in brightness with a period of approximately 749.5 seconds, or 12.5 minutes.^[5] By the middle of the 1970s, a number of additional variable white dwarfs had been found, but, like HL Tau 76, they were all white dwarfs of spectral type DA, with hydrogen-dominated atmospheres.^{[6] [7] [8]} In 1982, calculations by Don Winget and his coworkers suggested that helium-atmosphere DB white dwarfs with surface temperatures around 19,000 K should also pulsate.^{[9] , p. L67.} Winget then searched for such stars and found that GD 358 was a variable DB, or DBV, white dwarf.^[10] This was the first prediction of a class of variable stars before their observation.^{[11] , p. 89.} In 1985, this star was given the variable-star designation V777 Herculis, which is also another name for this class of variable stars.^{[12] ; [13] , p. 3525}

Notes and References

1. Winget . D E . 1998-12-14 . Asteroseismology of white dwarf stars . . 10 . 49 . 11247–11261 . 10.1088/0953-8984/10/49/014 . 1998JPCM...1011247W . 250749380 . 0953-8984.
2. http://adsabs.harvard.edu/abs/1971lpms.book.....G Lowell Proper Motion Survey: 8991 Stars with m > 8, PM > 0.26"/year in the Northern Hemisphere
3. http://adsabs.harvard.edu/abs/1967LowOB...7...49G A list of white dwarf suspects II : special objects of small proper motion from the Lowell survey
4. http://adsabs.harvard.edu/abs/1969ApJ...158..281G The Lowell Suspect White Dwarfs
5. http://adsabs.harvard.edu/abs/1968ApJ...153..151L A New Short-Period Blue Variable
6. http://adsabs.harvard.edu/abs/1976ApJ...207L..37R Observations of variable white dwarfs: one new variable and 35 nonvariables
7. http://adsabs.harvard.edu/abs/1976ApJ...209..853H High-frequency stellar oscillations. XI. The ZZ Ceti star BPM 30551
8. http://adsabs.harvard.edu/abs/1976ApJ...210L..35M BPM 31594: a new southern-hemisphere variable white dwarf
9. http://adsabs.harvard.edu/abs/1982ApJ...252L..65W Hydrogen-driving and the blue edge of compositionally stratified ZZ Ceti star models
10. Winget . D. E. . Robinson . E. L. . Nather . R. E. . Ed Nather . Fontaine . G. . 1982-11-01 . Photometric observations of GD 358 : OB white dwarfs do pulsate. . . 262 . L11–L15 . 10.1086/183902 . 1982ApJ...262L..11W . 0004-637X.
11. White Dwarf Stars, Steven D. Kawaler, in Stellar remnants, S. D. Kawaler, I. Novikov, and G. Srinivasan, edited by Georges Meynet and Daniel Schaerer, Berlin: Springer, 1997. Lecture notes for Saas-Fee advanced course number 25. .
12. http://adsabs.harvard.edu/abs/1985IBVS.2681....1K The 67th Name-List of Variable Stars
13. White dwarfs, Gilles Fontaine and François Wesemael, in Encyclopedia of Astronomy and Astrophysics, ed. Paul Murdin, Bristol and Philadelphia: Institute of Physics Publishing and London, New York and Tokyo: Nature Publishing Group, 2001. .