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Pulsating white dwarf

April 13, 2024

"V777 Herculis star" redirects here. For the star, see GD 358.

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;[1] DBV, or V777 Her, stars, with helium-dominated atmospheres and the spectral type DB;[2] 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;[3][4] 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.[5][6] A subtype of DQV stars, with carbon-dominated atmospheres, has also been proposed,[7] and in May 2012, the first extremely low mass variable (ELMV) white dwarf was reported.[8]

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.[9]

Types of pulsating white dwarf[4][7][8][10]
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;

DAV stars edit

Early calculations suggested that white dwarfs should vary with periods around 10 seconds, but searches in the 1960s failed to observe this.[11][12] The first variable white dwarf found was HL Tau 76; in 1965 and 1966, Arlo U. Landolt observed it to vary with a period of approximately 12.5 minutes.[13] The reason for this period being longer than predicted is that the variability of HL Tau 76, like that of the other pulsating variable white dwarfs known, arises from non-radial gravity wave pulsations.[14] In 1970, another white dwarf, Ross 548, was found to have the same type of variability as HL Tau 76;[15] in 1972, it was given the variable star designation ZZ Ceti.[16] The name ZZ Ceti also refers to this class of pulsating variable white dwarfs, which, as it consists of white dwarfs with hydrogen atmospheres, is also called DAV.[17] These stars have periods between 30 seconds and 25 minutes and are found in a rather narrow range of effective temperatures between about 12,500 and 11,100 K.[18] The measurement of the rate of change of period with time for the gravity wave pulsations in ZZ Ceti stars is a direct measurement of the cooling timescale for a DA white dwarf, which in turn can give an independent measurement of the age of the galactic disk.[19]

DBV stars edit

 
A white-light light curve for GD 358, adapted from Winget et al. (1982)[20]

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.[21] Winget then searched for such stars and found that GD 358 was a variable DB, or DBV, white dwarf.[20] This was the first prediction of a class of variable stars before their observation.[22] In 1985, this star was given the designation V777 Her, which is also another name for this class of variable stars.[2][23] These stars have effective temperatures around 25,000K.[24]

GW Vir stars edit

 
A light curve for GW Virginis, adapted from Winget et al. (1985)[25]

The third known class of pulsating variable white dwarfs is the GW Vir stars, sometimes subdivided into DOV and PNNV stars. Their prototype is PG 1159-035.[5] This star (also the prototype for the class of PG 1159 stars) was observed to vary in 1979,[26] and was given the variable star designation GW Vir in 1985,[23] giving its name to the class. These stars are not, strictly speaking, white dwarfs; rather, they are stars which are in a position on the Hertzsprung-Russell diagram between the asymptotic giant branch and the white dwarf region. They may be called pre-white dwarfs.[5][6] They are hot, with surface temperatures between 75,000 K and 200,000 K, and have atmospheres dominated by helium, carbon, and oxygen. They may have relatively low surface gravities (log g ≤ 6.5).[27] It is believed that these stars will eventually cool and become DO white dwarfs.[5]

The periods of the vibrational modes of GW Vir stars range from about 300 to about 5,000 seconds.[27] How pulsations are excited in GW Vir stars was first studied in the 1980s[28] but remained puzzling for almost twenty years.[29] From the beginning, the excitation mechanism was thought to be caused by the so-called κ-mechanism associated with ionized carbon and oxygen in the envelope below the photosphere, but it was thought this mechanism would not function if helium was present in the envelope. However, it now appears that instability can exist even in the presence of helium.[30]

DQV stars edit

A new class of white dwarfs, with spectral type DQ and hot, carbon-dominated atmospheres, has recently been discovered by Patrick Dufour, James Liebert and their coworkers.[31] Theoretically, such white dwarfs should pulsate at temperatures where their atmospheres are partially ionized. Observations made at McDonald Observatory suggest that SDSS J142625.71+575218.3 is such a white dwarf; if so, it would be the first member of a new, DQV, class, of pulsating white dwarfs. However, it is also possible that it is a white dwarf binary system with a carbon-oxygen accretion disk.[7]

See also edit

Notes edit

  1. ^ Koester & Chanmugam 1990, p. 891–895.
  2. ^ a b Murdin, Paul, ed. (2001). Encyclopedia of Astronomy and Astrophysics. Bristol: Nature Publishing Group. p. 3525. ISBN 978-0-333-75088-9.
  3. ^ Nagel, T.; Werner, K. (1 November 2004). "Detection of non-radial g-mode pulsations in the newly discovered PG 1159 star HE 1429-1209". Astronomy and Astrophysics. 426 (2): L45–L48. arXiv:astro-ph/0409243. Bibcode:2004A&A...426L..45N. doi:10.1051/0004-6361:200400079. ISSN 0004-6361. S2CID 9481357. §1.
  4. ^ a b Quirion, Fontaine & Brassard 2007, §1.1, 1.2.
  5. ^ a b c d Quirion, Fontaine & Brassard 2007, §1.1.
  6. ^ a b O'Brien, M. S. (1 April 2000). "The Extent and Cause of the Pre-White Dwarf Instability Strip". The Astrophysical Journal. 532 (2): 1078–1088. arXiv:astro-ph/9910495. Bibcode:2000ApJ...532.1078O. doi:10.1086/308613. ISSN 0004-637X. S2CID 115958740.
  7. ^ a b c Montgomery, M. H.; Williams, Kurtis A.; Winget, D. E.; Dufour, Patrick; DeGennaro, Steven; Liebert, James (2008). "SDSS J142625.71+575218.3: A Prototype for a New Class of Variable White Dwarf". The Astrophysical Journal Letters. 678 (1): L51. arXiv:0803.2646. Bibcode:2008ApJ...678L..51M. doi:10.1086/588286. ISSN 1538-4357. S2CID 15385909.
  8. ^ a b Hermes, J. J.; Montgomery, M. H.; Winget, D. E.; Brown, Warren R.; Kilic, Mukremin; Kenyon, Scott J. (1 May 2012). "SDSS J184037.78+642312.3: The First Pulsating Extremely Low Mass White Dwarf". The Astrophysical Journal Letters. 750 (2): L28. arXiv:1204.1338. Bibcode:2012ApJ...750L..28H. doi:10.1088/2041-8205/750/2/L28. ISSN 0004-637X. S2CID 119188878.
  9. ^ Winget, D. E. (1998). "Asteroseismology of white dwarf stars". Journal of Physics: Condensed Matter. 10 (49): 11247–11261. Bibcode:1998JPCM...1011247W. doi:10.1088/0953-8984/10/49/014. ISSN 0953-8984. S2CID 250749380.
  10. ^ Association Française des Observateurs d'Etoiles Variables. . Centre de Données astronomiques de Strasbourg. Archived from the original on 2007-02-05. Retrieved 2007-06-06.
  11. ^ Koester & Chanmugam 1990, § 7.1.1.
  12. ^ Lawrence, George M.; Ostriker, Jeremiah P.; Hesser, James E. (1 June 1967). "Ultrashort-Period Stellar Oscillations. I. Results from White Dwarfs, Old Novae, Central Stars of Planetary Nebulae, 3c 273, and Scorpius XR-1". The Astrophysical Journal Letters. 148: L161–L163. Bibcode:1967ApJ...148L.161L. doi:10.1086/180037. ISSN 0004-637X.
  13. ^ Landolt, Arlo U. (1 July 1968). "A New Short-Period Blue Variable". The Astrophysical Journal. 153: 151–164. Bibcode:1968ApJ...153..151L. doi:10.1086/149645. ISSN 0004-637X.
  14. ^ Koester & Chanmugam 1990, § 7.
  15. ^ Lasker, Barry M.; Hesser, James E. (1 February 1971). "High-Frequency Stellar Oscillations.VI. R548, a Periodically Variable White Dwarf". The Astrophysical Journal Letters. 163: L89–L93. Bibcode:1971ApJ...163L..89L. doi:10.1086/180673. ISSN 0004-637X.
  16. ^ Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (1 September 1972). "58th Name-List of Variable Stars". Information Bulletin on Variable Stars. 717: 1. Bibcode:1972IBVS..717....1K. ISSN 0374-0676.
  17. ^ Koester & Chanmugam 1990, pp. 891, 895.
  18. ^ Bergeron, P.; Fontaine, G.; Billères, M.; Boudreault, S.; Green, E. M. (2004). "On the Purity of the ZZ Ceti Instability Strip: Discovery of More Pulsating DA White Dwarfs on the Basis of Optical Spectroscopy". The Astrophysical Journal. 600 (1): 404–8. arXiv:astro-ph/0309483. Bibcode:2004ApJ...600..404B. doi:10.1086/379808. ISSN 0004-637X. S2CID 16636294.
  19. ^ Kepler, S. O.; Vauclair, G.; Nather, R. E.; Winget, D. E.; Robinson, E. L. (1989). G117-B15A - How is it evolving?. IAU Colloq. 114: White Dwarfs. Vol. 328. pp. 341–345. doi:10.1007/3-540-51031-1_344.
  20. ^ a b Winget, D. E.; Robinson, E. L.; Nather, R. E.; Fontaine, G. (1 November 1982). "Photometric observations of GD 358 - DB white dwarfs do pulsate". The Astrophysical Journal Letters. 262: L11–L15. Bibcode:1982ApJ...262L..11W. doi:10.1086/183902. ISSN 0004-637X.
  21. ^ Winget, D. E.; van Horn, H. M.; Tassoul, M.; Fontaine, G.; Hansen, C. J.; Carroll, B. W. (1 January 1982). "Hydrogen-driving and the blue edge of compositionally stratified ZZ Ceti star models". The Astrophysical Journal Letters. 252: L67. Bibcode:1982ApJ...252L..65W. doi:10.1086/183721. ISSN 0004-637X.
  22. ^ Kawaler, Steven D.; Novikov, I. D.; Srinivasan, G. (1997). Meynet, G.; Schaerer (eds.). Stellar remnants. Saas-Fee advanced course 25 lecture notes. Berlin: Springer. p. 89. ISBN 978-3-540-61520-0. Lecture notes for Saas-Fee advanced course number 25.
  23. ^ a b Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Perova, N. B. (1 March 1985). "The 67th Name-List of Variable Stars". Information Bulletin on Variable Stars. 2681: 1. Bibcode:1985IBVS.2681....1K. ISSN 0374-0676.
  24. ^ Koester & Chanmugam 1990, p. 895.
  25. ^ Winget, D. E.; Kepler, S. O.; Robinson, E. L.; Nather, R. E.; O’Donoghue, Darragh (May 1985). "A measurement of secular evolution in the pre-white dwarf star PG 1159-035". The Astrophysical Journal. 292: 606–613. Bibcode:1985ApJ...292..606W. doi:10.1086/163193.
  26. ^ McGraw, J. T.; Liebert, James; Starrfield, S. G.; Green, R. (1979). PG1159-035: A new, hot, non-DA pulsating degenerate. IAU Colloq. 53: White Dwarfs and Variable Degenerate Stars. pp. 377–381. Bibcode:1979wdvd.coll..377M.
  27. ^ a b Quirion, Fontaine & Brassard 2007, Table 1.
  28. ^ Cox, Arthur N. (1 March 2003). "A Pulsation Mechanism for GW Virginis Variables". The Astrophysical Journal. 585 (2): 975–982. Bibcode:2003ApJ...585..975C. doi:10.1086/346228. ISSN 0004-637X.
  29. ^ Cox, A. N. (1 May 2002). An Instability Mechanism for GW Vir Variables. Bulletin of the American Astronomical Society. Vol. 200. p. 85.07. Bibcode:2002AAS...200.8507C.
  30. ^ Córsico, A. H.; Althaus, L. G.; Miller Bertolami, M. M. (1 October 2006). "New nonadiabatic pulsation computations on full PG 1159 evolutionary models: the theoretical GW Virginis instability strip revisited". Astronomy and Astrophysics. 458 (1): 259–267. arXiv:astro-ph/0607012. Bibcode:2006A&A...458..259C. doi:10.1051/0004-6361:20065423. ISSN 0004-6361. S2CID 16700443. §1.
  31. ^ Dufour, P.; Liebert, James; Fontaine, G.; Behara, N. (November 2007). "White dwarf stars with carbon atmospheres". Nature. 450 (7169): 522–524. arXiv:0711.3227. Bibcode:2007Natur.450..522D. doi:10.1038/nature06318. ISSN 0028-0836. PMID 18033290. S2CID 4398697.

References edit

  • Koester, D.; Chanmugam, G. (1990). "REVIEW: Physics of white dwarf stars" (PDF). Reports on Progress in Physics. 53 (7): 837–915. Bibcode:1990RPPh...53..837K. doi:10.1088/0034-4885/53/7/001. ISSN 0034-4885. S2CID 250915046.
  • Quirion, P.O.; Fontaine, G.; Brassard, P. (1 July 2007). "Mapping the Instability Domains of GW Vir Stars in the Effective Temperature-Surface Gravity Diagram". The Astrophysical Journal Supplement Series. 171 (1): 219–248. Bibcode:2007ApJS..171..219Q. doi:10.1086/513870. ISSN 0067-0049.

External links and further reading edit

  • Variable White Dwarf Data Tables, Paul A. Bradley, 22 March 2005 version. Accessed online June 7, 2007.
  • A Progress Report on the Empirical Determination of the ZZ Ceti Instability Strip, A. Gianninas, P. Bergeron, and G. Fontaine, arXiv:astro-ph/0612043.
  • Asteroseismology of white dwarf stars, D. E. Winget, Journal of Physics: Condensed Matter 10, #49 (December 14, 1998), pp. 11247–11261. DOI 10.1088/0953-8984/10/49/014.

April 13, 2024
pulsating, white, dwarf, v777, herculis, star, redirects, here, star, pulsating, white, dwarf, white, dwarf, star, whose, luminosity, varies, radial, gravity, wave, pulsations, within, itself, known, types, pulsating, white, dwarfs, include, ceti, stars, with,. V777 Herculis star redirects here For the star see GD 358 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 1 DBV or V777 Her stars with helium dominated atmospheres and the spectral type DB 2 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 3 4 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 5 6 A subtype of DQV stars with carbon dominated atmospheres has also been proposed 7 and in May 2012 the first extremely low mass variable ELMV white dwarf was reported 8 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 9 Types of pulsating white dwarf 4 7 8 10 DAV GCVS ZZA DA spectral type having only hydrogen absorption lines in its spectrumDBV GCVS ZZB DB spectral type having only helium absorption lines in its spectrumGW Vir GCVS ZZO Atmosphere mostly C He and O may be divided into DOV and PNNV starsDQV DQ spectral type hot carbon dominated atmosphereELMV DA spectral type 0 2M displaystyle lesssim 0 2M odot Contents 1 DAV stars 2 DBV stars 3 GW Vir stars 4 DQV stars 5 See also 6 Notes 7 References 8 External links and further readingDAV stars editEarly calculations suggested that white dwarfs should vary with periods around 10 seconds but searches in the 1960s failed to observe this 11 12 The first variable white dwarf found was HL Tau 76 in 1965 and 1966 Arlo U Landolt observed it to vary with a period of approximately 12 5 minutes 13 The reason for this period being longer than predicted is that the variability of HL Tau 76 like that of the other pulsating variable white dwarfs known arises from non radial gravity wave pulsations 14 In 1970 another white dwarf Ross 548 was found to have the same type of variability as HL Tau 76 15 in 1972 it was given the variable star designation ZZ Ceti 16 The name ZZ Ceti also refers to this class of pulsating variable white dwarfs which as it consists of white dwarfs with hydrogen atmospheres is also called DAV 17 These stars have periods between 30 seconds and 25 minutes and are found in a rather narrow range of effective temperatures between about 12 500 and 11 100 K 18 The measurement of the rate of change of period with time for the gravity wave pulsations in ZZ Ceti stars is a direct measurement of the cooling timescale for a DA white dwarf which in turn can give an independent measurement of the age of the galactic disk 19 DBV stars edit nbsp A white light light curve for GD 358 adapted from Winget et al 1982 20 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 21 Winget then searched for such stars and found that GD 358 was a variable DB or DBV white dwarf 20 This was the first prediction of a class of variable stars before their observation 22 In 1985 this star was given the designation V777 Her which is also another name for this class of variable stars 2 23 These stars have effective temperatures around 25 000K 24 GW Vir stars edit nbsp A light curve for GW Virginis adapted from Winget et al 1985 25 The third known class of pulsating variable white dwarfs is the GW Vir stars sometimes subdivided into DOV and PNNV stars Their prototype is PG 1159 035 5 This star also the prototype for the class of PG 1159 stars was observed to vary in 1979 26 and was given the variable star designation GW Vir in 1985 23 giving its name to the class These stars are not strictly speaking white dwarfs rather they are stars which are in a position on the Hertzsprung Russell diagram between the asymptotic giant branch and the white dwarf region They may be called pre white dwarfs 5 6 They are hot with surface temperatures between 75 000 K and 200 000 K and have atmospheres dominated by helium carbon and oxygen They may have relatively low surface gravities log g 6 5 27 It is believed that these stars will eventually cool and become DO white dwarfs 5 The periods of the vibrational modes of GW Vir stars range from about 300 to about 5 000 seconds 27 How pulsations are excited in GW Vir stars was first studied in the 1980s 28 but remained puzzling for almost twenty years 29 From the beginning the excitation mechanism was thought to be caused by the so called k mechanism associated with ionized carbon and oxygen in the envelope below the photosphere but it was thought this mechanism would not function if helium was present in the envelope However it now appears that instability can exist even in the presence of helium 30 DQV stars editA new class of white dwarfs with spectral type DQ and hot carbon dominated atmospheres has recently been discovered by Patrick Dufour James Liebert and their coworkers 31 Theoretically such white dwarfs should pulsate at temperatures where their atmospheres are partially ionized Observations made at McDonald Observatory suggest that SDSS J142625 71 575218 3 is such a white dwarf if so it would be the first member of a new DQV class of pulsating white dwarfs However it is also possible that it is a white dwarf binary system with a carbon oxygen accretion disk 7 See also editG 117 B15A Instability strip Stellar pulsationNotes edit Koester amp Chanmugam 1990 p 891 895 a b Murdin Paul ed 2001 Encyclopedia of Astronomy and Astrophysics Bristol Nature Publishing Group p 3525 ISBN 978 0 333 75088 9 Nagel T Werner K 1 November 2004 Detection of non radial g mode pulsations in the newly discovered PG 1159 star HE 1429 1209 Astronomy and Astrophysics 426 2 L45 L48 arXiv astro ph 0409243 Bibcode 2004A amp A 426L 45N doi 10 1051 0004 6361 200400079 ISSN 0004 6361 S2CID 9481357 1 a b Quirion Fontaine amp Brassard 2007 1 1 1 2 a b c d Quirion Fontaine amp Brassard 2007 1 1 a b O Brien M S 1 April 2000 The Extent and Cause of the Pre White Dwarf Instability Strip The Astrophysical Journal 532 2 1078 1088 arXiv astro ph 9910495 Bibcode 2000ApJ 532 1078O doi 10 1086 308613 ISSN 0004 637X S2CID 115958740 a b c Montgomery M H Williams Kurtis A Winget D E Dufour Patrick DeGennaro Steven Liebert James 2008 SDSS J142625 71 575218 3 A Prototype for a New Class of Variable White Dwarf The Astrophysical Journal Letters 678 1 L51 arXiv 0803 2646 Bibcode 2008ApJ 678L 51M doi 10 1086 588286 ISSN 1538 4357 S2CID 15385909 a b Hermes J J Montgomery M H Winget D E Brown Warren R Kilic Mukremin Kenyon Scott J 1 May 2012 SDSS J184037 78 642312 3 The First Pulsating Extremely Low Mass White Dwarf The Astrophysical Journal Letters 750 2 L28 arXiv 1204 1338 Bibcode 2012ApJ 750L 28H doi 10 1088 2041 8205 750 2 L28 ISSN 0004 637X S2CID 119188878 Winget D E 1998 Asteroseismology of white dwarf stars Journal of Physics Condensed Matter 10 49 11247 11261 Bibcode 1998JPCM 1011247W doi 10 1088 0953 8984 10 49 014 ISSN 0953 8984 S2CID 250749380 Association Francaise des Observateurs d Etoiles Variables ZZ Ceti variables Centre de Donnees astronomiques de Strasbourg Archived from the original on 2007 02 05 Retrieved 2007 06 06 Koester amp Chanmugam 1990 7 1 1 Lawrence George M Ostriker Jeremiah P Hesser James E 1 June 1967 Ultrashort Period Stellar Oscillations I Results from White Dwarfs Old Novae Central Stars of Planetary Nebulae 3c 273 and Scorpius XR 1 The Astrophysical Journal Letters 148 L161 L163 Bibcode 1967ApJ 148L 161L doi 10 1086 180037 ISSN 0004 637X Landolt Arlo U 1 July 1968 A New Short Period Blue Variable The Astrophysical Journal 153 151 164 Bibcode 1968ApJ 153 151L doi 10 1086 149645 ISSN 0004 637X Koester amp Chanmugam 1990 7 Lasker Barry M Hesser James E 1 February 1971 High Frequency Stellar Oscillations VI R548 a Periodically Variable White Dwarf The Astrophysical Journal Letters 163 L89 L93 Bibcode 1971ApJ 163L 89L doi 10 1086 180673 ISSN 0004 637X Kukarkin B V Kholopov P N Kukarkina N P Perova N B 1 September 1972 58th Name List of Variable Stars Information Bulletin on Variable Stars 717 1 Bibcode 1972IBVS 717 1K ISSN 0374 0676 Koester amp Chanmugam 1990 pp 891 895 Bergeron P Fontaine G Billeres M Boudreault S Green E M 2004 On the Purity of the ZZ Ceti Instability Strip Discovery of More Pulsating DA White Dwarfs on the Basis of Optical Spectroscopy The Astrophysical Journal 600 1 404 8 arXiv astro ph 0309483 Bibcode 2004ApJ 600 404B doi 10 1086 379808 ISSN 0004 637X S2CID 16636294 Kepler S O Vauclair G Nather R E Winget D E Robinson E L 1989 G117 B15A How is it evolving IAU Colloq 114 White Dwarfs Vol 328 pp 341 345 doi 10 1007 3 540 51031 1 344 a b Winget D E Robinson E L Nather R E Fontaine G 1 November 1982 Photometric observations of GD 358 DB white dwarfs do pulsate The Astrophysical Journal Letters 262 L11 L15 Bibcode 1982ApJ 262L 11W doi 10 1086 183902 ISSN 0004 637X Winget D E van Horn H M Tassoul M Fontaine G Hansen C J Carroll B W 1 January 1982 Hydrogen driving and the blue edge of compositionally stratified ZZ Ceti star models The Astrophysical Journal Letters 252 L67 Bibcode 1982ApJ 252L 65W doi 10 1086 183721 ISSN 0004 637X Kawaler Steven D Novikov I D Srinivasan G 1997 Meynet G Schaerer eds Stellar remnants Saas Fee advanced course 25 lecture notes Berlin Springer p 89 ISBN 978 3 540 61520 0 Lecture notes for Saas Fee advanced course number 25 a b Kholopov P N Samus N N Kazarovets E V Perova N B 1 March 1985 The 67th Name List of Variable Stars Information Bulletin on Variable Stars 2681 1 Bibcode 1985IBVS 2681 1K ISSN 0374 0676 Koester amp Chanmugam 1990 p 895 Winget D E Kepler S O Robinson E L Nather R E O Donoghue Darragh May 1985 A measurement of secular evolution in the pre white dwarf star PG 1159 035 The Astrophysical Journal 292 606 613 Bibcode 1985ApJ 292 606W doi 10 1086 163193 McGraw J T Liebert James Starrfield S G Green R 1979 PG1159 035 A new hot non DA pulsating degenerate IAU Colloq 53 White Dwarfs and Variable Degenerate Stars pp 377 381 Bibcode 1979wdvd coll 377M a b Quirion Fontaine amp Brassard 2007 Table 1 Cox Arthur N 1 March 2003 A Pulsation Mechanism for GW Virginis Variables The Astrophysical Journal 585 2 975 982 Bibcode 2003ApJ 585 975C doi 10 1086 346228 ISSN 0004 637X Cox A N 1 May 2002 An Instability Mechanism for GW Vir Variables Bulletin of the American Astronomical Society Vol 200 p 85 07 Bibcode 2002AAS 200 8507C Corsico A H Althaus L G Miller Bertolami M M 1 October 2006 New nonadiabatic pulsation computations on full PG 1159 evolutionary models the theoretical GW Virginis instability strip revisited Astronomy and Astrophysics 458 1 259 267 arXiv astro ph 0607012 Bibcode 2006A amp A 458 259C doi 10 1051 0004 6361 20065423 ISSN 0004 6361 S2CID 16700443 1 Dufour P Liebert James Fontaine G Behara N November 2007 White dwarf stars with carbon atmospheres Nature 450 7169 522 524 arXiv 0711 3227 Bibcode 2007Natur 450 522D doi 10 1038 nature06318 ISSN 0028 0836 PMID 18033290 S2CID 4398697 References editKoester D Chanmugam G 1990 REVIEW Physics of white dwarf stars PDF Reports on Progress in Physics 53 7 837 915 Bibcode 1990RPPh 53 837K doi 10 1088 0034 4885 53 7 001 ISSN 0034 4885 S2CID 250915046 Quirion P O Fontaine G Brassard P 1 July 2007 Mapping the Instability Domains of GW Vir Stars in the Effective Temperature Surface Gravity Diagram The Astrophysical Journal Supplement Series 171 1 219 248 Bibcode 2007ApJS 171 219Q doi 10 1086 513870 ISSN 0067 0049 External links and further reading editVariable White Dwarf Data Tables Paul A Bradley 22 March 2005 version Accessed online June 7 2007 A Progress Report on the Empirical Determination of the ZZ Ceti Instability Strip A Gianninas P Bergeron and G Fontaine arXiv astro ph 0612043 Asteroseismology of white dwarf stars D E Winget Journal of Physics Condensed Matter 10 49 December 14 1998 pp 11247 11261 DOI 10 1088 0953 8984 10 49 014 Retrieved from https en wikipedia org w index php title Pulsating white dwarf amp oldid 1199505783 GW Vir stars, wikipedia, wiki, book, books, library,

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