GD 66

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GD 66
File:GD66LightCurve.png
A light curve for GD 66, adapted from Fontaine et al. (1985)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga[2]
Right ascension 05h 20m 38.32s[3]
Declination +30° 48′ 23.9″[3]
Apparent magnitude (V) 15.6[4]
Characteristics
Evolutionary stage white dwarf[5]
Spectral type DA4.1[6]
U−B color index −0.59[7]
B−V color index +0.22[7]
Variable type ZZA[4]
Astrometry
Proper motion (μ) RA: +57.213[3] mas/yr
Dec.: −122.348[3] mas/yr
Parallax (π)17.5116±0.0387 mas[3]
Distance186.3 ± 0.4 ly
(57.1 ± 0.1 pc)
Absolute magnitude (MV)11.79[6]
Details
Mass0.64±0.03[8] M☉
Surface gravity (log g)8.05[9] cgs
Temperature11,980[9] K
Age1.2–1.7[8] Gyr
Other designations
GD 66, 361 Aurigae, EGGR 572, WD 0517+30, WD 0517+307, 2MASS J05203829+3048239[10]
Database references
SIMBADdata

GD 66 or V361 Aurigae is a 0.64 solar mass (M☉)[8] pulsating white dwarf star located 170 light years from Earth[5] in the Auriga constellation. The estimated cooling age of the white dwarf is 500 million years.[8] 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.[8] The total age of the star is thus estimated to be in the range 1.2 to 1.7 billion years.[8]

In 1983, Noël Dolez et al. discovered that GD 66 is a variable star, from photometric data obtained at Haute-Provence Observatory.[11] It was given its variable star designation, V361 Aurigae, in 1985.[12] 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.[5] 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.[8] Investigation of a separate pulsation mode revealed timing variations in antiphase with the variations in the originally-analysed pulsation mode.[13] 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.[14]

References

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  1. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  2. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Constellation record for this object at VizieR.
  3. ^ a b c d e Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR3 record for this source at VizieR.
  4. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  5. ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  6. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  7. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  8. ^ a b c d e f g Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  9. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  10. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  11. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  12. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  13. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  14. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
[edit | edit source]
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