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GD 66

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(Redirected from GD 66 b) Star in the constellation Auriga
GD 66

A light curve for GD 66, adapted from Fontaine et al. (1985)
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension 05 20 38.31
Declination +30° 48′ 24.1″
Apparent magnitude (V) 15.56
Characteristics
Spectral type DA
U−B color index -0.59
B−V color index 0.22
Variable type Pulsating white dwarf
Astrometry
Proper motion (μ) RA: 54 mas/yr
Dec.: −120 mas/yr
Distance170 ly
(51 pc)
Absolute magnitude (MV)12
Details
Mass0.64 ± 0.03 M
Surface gravity (log g)8.05 cgs
Temperature11980 K
Age1.2–1.7 billion years
Other designations
V361 Aurigae, GD 66, 2MASS J05203829+3048239, WD 0517+30, EGGR 572, WD 0517+307
Database references
SIMBADdata

GD 66 or V361 Aurigae is a 0.64 solar mass (M) pulsating white dwarf star located 170 light years from Earth in the Auriga constellation. The estimated cooling age of the white dwarf is 500 million years. Models of the relationship between the initial mass of a star and its final mass as a white dwarf star suggest that when the star was on the main sequence it had a mass of approximately 2.5 M, which implies its lifetime was around 830 million years. The total age of the star is thus estimated to be in the range 1.2 to 1.7 billion years.

In 1983, Noël Dolez et al. discovered that GD 66 is a variable star, from photometric data obtained at Haute-Provence Observatory. It was given its variable star designation, V361 Aurigae, in 1985. The star is a pulsating white dwarf of type DAV, with an extremely stable period. Small variations in the phase of pulsation led to the suggestion that the star was being orbited by a giant planet which caused the pulsations to be delayed due to the varying distance to the star caused by the reflex motion about the system's centre-of-mass. Observations with the Spitzer Space Telescope failed to directly detect the planet, which put an upper limit on the mass of 5–6 Jupiter masses. Investigation of a separate pulsation mode revealed timing variations in antiphase with the variations in the originally-analysed pulsation mode. This would not be the case if the variations were caused by an orbiting planet, and thus the timing variations must have a different cause. This illustrates the potential dangers of attempting to detect planets by white dwarf pulsation timing.

References

  1. Fontaine, G.; Wesemael, F.; Bergeron, P.; Lacombe, P.; Lamontagne, R. (July 1985). "The demise of mode identification in the pulsating DA white dwarf GD 66". The Astrophysical Journal. 294: 339–344. Bibcode:1985ApJ...294..339F. doi:10.1086/163301. Retrieved 2 November 2021.
  2. ^ "V* V361 Aur". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2008-12-19.
  3. ^ Mullally, F.; et al. (2008). "Limits on Planets around Pulsating White Dwarf Stars". The Astrophysical Journal. 676 (1): 573–583. arXiv:0801.3104. Bibcode:2008ApJ...676..573M. doi:10.1086/528672. S2CID 123684051.
  4. ^ Mullally, F.; et al. (2009). "Spitzer Planet Limits around the Pulsating White Dwarf GD66". The Astrophysical Journal. 694 (1): 327–331. arXiv:0812.2951. Bibcode:2009ApJ...694..327M. doi:10.1088/0004-637X/694/1/327. S2CID 16241754.
  5. ^ Bergeron, P.; et al. (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): 404–408. arXiv:astro-ph/0309483. Bibcode:2004ApJ...600..404B. doi:10.1086/379808. S2CID 16636294.
  6. Dolez, N.; Vauclair, G.; Chevreton, M. (May 1983). "Identification of gravity modes in the newly discovered ZZ Ceti variable GD 66". Astronomy and Astrophysics. 121: L23–L26. Bibcode:1983A&A...121L..23D. Retrieved 30 November 2024.
  7. Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Perova, N. B. (March 1985). "The 67th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 2681. Bibcode:1985IBVS.2681....1K. Retrieved 30 November 2024.
  8. Hermes, James J. (2013). Complications to the Planetary Hypothesis for GD 66. AAS Meeting #221. American Astronomical Society. Bibcode:2013AAS...22142404H.
  9. Hermes, J. J. (2012). 8 Years On: A Search for Planets Around Isolated White Dwarfs (PDF). Planets around Stellar Remnants. Archived from the original (PDF) on 2014-12-27.

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