HL Tau 76

A white-light light curve light curve for HL Tau 76, adapted from Warner and Nather (1972) [1]
Observation data Epoch J2000.0       Equinox J2000.0 ( 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
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

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]

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]

Notes and references