HL Tau 76 is a

variable Variable may refer to: * Variable (computer science), a symbolic name associated with a value and whose associated value may be changed * Variable (mathematics), a symbol that represents a quantity in a mathematical expression, as used in many ...

white dwarf A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes ...

star of the DAV (or ZZ Ceti) type. It was observed by G. Haro and W. J. Luyten in 1961, and was the first

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. Like other DAV white dwarfs, its variability arises from non-radial gravity wave pulsations within itself.^{, § 7.} Later observation and analysis has found HL Tau 76 to pulsate in over 40 independent

vibrational mode A normal mode of a dynamical system is a pattern of motion in which all parts of the system move sinusoidally with the same frequency and with a fixed phase relation. The free motion described by the normal modes takes place at fixed frequencies. ...

s, with periods between 380 seconds and 1390 seconds. 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 Guillermo Haro Barraza (; 21 March 1913 – 26 April 1988) was a Mexican astronomer. Through his own astronomical research and the formation of new institutions, Haro was influential in the development of modern observational astronomy in M ...

and

Willem Jacob Luyten Willem Jacob Luyten (March 7, 1899 – November 21, 1994) was a Dutch-American astronomer. "Willem Jacob Luyten", ''Marquis Who's Who'', 2006. Life Jacob Luyten was born in Semarang, Java, at the time part of the Dutch East Indies. His ...

. 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. It was then included in the 57th name-list of variable stars and given the

variable star designation In astronomy, a variable star designation is a unique identifier given to variable stars. It uses a variation on the Bayer designation format, with an identifying label (as described below) preceding the Latin genitive of the name of the conste ...

V441 Tauri. The unusual designation HL Tau 76 continues to be used by most authors.

Notes and references

{{DEFAULTSORT:HL Tau 76 Taurus (constellation) Pulsating white dwarfs Tauri, V411