GD 66
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Auriga |
| Right ascension | Template:RA[2] |
| Declination | Template:DEC[2] |
| Apparent magnitude (V) | 15.56[2] |
| Characteristics | |
| Spectral type | DA[2] |
| U−B Template:Engvar | -0.59Script error: No such module "Unsubst". |
| B−V Template:Engvar | 0.22[2] |
| Variable type | Pulsating white dwarf |
| Astrometry | |
| Proper motion (μ) | RA: 54[2] mas/yr Dec.: −120[2] mas/yr |
| Distance | 170[3] ly (51 pc) |
| Absolute magnitude (MV) | 12 |
| Details | |
| Mass | 0.64 ± 0.03[4] Template:Solar mass |
| Surface gravity (log g) | 8.05[5] cgs |
| Temperature | 11980[5] K |
| Age | 1.2–1.7 billion[4] years |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| V361 Aurigae, GD 66, 2MASS J05203829+3048239, WD 0517+30, EGGR 572, WD 0517+307 | |
| Database references | |
| SIMBAD | data |
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GD 66 or V361 Aurigae is a 0.64 solar mass (Template:Solar mass)[4] pulsating white dwarf star located 170 light years from Earth[3] in the Auriga constellation. The estimated cooling age of the white dwarf is 500 million years.[4] 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 Template:Solar mass, which implies its lifetime was around 830 million years.[4] The total age of the star is thus estimated to be in the range 1.2 to 1.7 billion years.[4]
In 1983, Noël Dolez et al. discovered that GD 66 is a variable star, from photometric data obtained at Haute-Provence Observatory.[6] It was given its variable star designation, V361 Aurigae, in 1985.[7] 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.[3] 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.[4] Investigation of a separate pulsation mode revealed timing variations in antiphase with the variations in the originally-analysed pulsation mode.[8] 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.[9]
References
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External links
- V361 Aurigae Catalog
- WD 0517+307 Catalog
- Image GD 66