HL Tau 76
Star in the constellation Taurus
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HL Tau 76 is a variable white dwarf star of the DAV (or ZZ Ceti) type. It was observed by G. Haro and W. J. Luyten in 1961,[8][9] and was the first variable white dwarf discovered when, in 1968, Arlo U. Landolt found that it varied in brightness with a period of approximately 749.5 seconds, or 12.5 minutes.[9] Like other DAV white dwarfs, its variability arises from non-radial gravity wave pulsations within itself.[10], § 7. Later observation and analysis has found HL Tau 76 to pulsate in over 40 independent vibrational modes, with periods between 380 seconds and 1390 seconds.[11]
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Taurus |
| Right ascension | 04h 18m 56.638s[2] |
| Declination | +27° 17′ 48.31″[2] |
| Apparent magnitude (V) | 14.1–15.28[3] |
| Characteristics | |
| Evolutionary stage | white dwarf[4] |
| Spectral type | DA4.3[4] |
| B−V color index | 0.2[5] |
| Variable type | DAV (ZZ Ceti)[3] |
| Astrometry | |
| Proper motion (μ) | RA: 62.600[2] mas/yr Dec.: −72.819[2] mas/yr |
| Parallax (π) | 20.7244±0.0338 mas[2] |
| Distance | 157.4 ± 0.3 ly (48.25 ± 0.08 pc) |
| Absolute magnitude (MV) | 11.69[4] |
| Details | |
| Mass | 0.575±0.005[6] M☉ |
| Radius | 0.0162[6] R☉ |
| Luminosity | 0.00389[6] L☉ |
| Surface gravity (log g) | 7.8[7] cgs |
| Temperature | 11,375±30[6] K |
| Other designations | |
| EGGR 265, V411 Tau, WD 0416+272[5] | |
| Database references | |
| SIMBAD | data |
The designation HL Tau 76 derives from the discovery of this star as a white dwarf, when it was described as Taurus no.76 in a publication authored by Guillermo Haro and Willem Jacob Luyten.[8] The exact designation HL Tau 76 was then used in subsequent papers, including one giving the star its designation EGGR 265 where it was noted to be variable.[12] It was then included in the 57th name-list of variable stars and given the variable star designation V441 Tauri.[13] The unusual designation HL Tau 76 continues to be used by most authors.[14]