Ross 548

Ross 548 is a white dwarf in the equatorial constellation of Cetus.^[7] With a mean apparent visual magnitude of 14.2^[3] it is much too faint to be visible to the naked eye. Based on parallax measurements, it is located at a distance of 107 light years from the Sun.^[2] It was found to be variable in 1970^[8] and in 1972 it was given the variable star designation ZZ Ceti.^[9] This is a pulsating white dwarf of the DAV type that is the prototype of the ZZ Ceti variable class.^{[10], pp. 891, 895.[3]}

Ross 548

A light curve for ZZ Ceti, adapted from Stover et al. (1980)[1]
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Cetus
Right ascension	01h 36m 13.61558s[2]
Declination	−11° 20′ 32.6318″[2]
Apparent magnitude (V)	14.16±0.01[3]
Characteristics
Evolutionary stage	White dwarf
Spectral type	DA4.0[4]
U−B color index	−0.5[5]
B−V color index	0.2[5]
Variable type	ZZ Cet (DAV)[5]
Astrometry
Proper motion (μ)	RA: +460.845[2] mas/yr Dec.: −116.448[2] mas/yr
Parallax (π)	30.5249±0.0546 mas[2]
Distance	106.8 ± 0.2 ly (32.76 ± 0.06 pc)
Absolute magnitude (MV)	11.78±0.06[6]
Details[6]
Mass	0.65±0.02 M☉
Radius	0.0118±0.0002 R☉
Luminosity	0.0029±0.0002 L☉
Surface gravity (log g)	8.108±0.025 cgs
Temperature	12,281±125 K
Rotation	37.84±1.99 h
Other designations
ZZ Cet, EGGR 10, G 271-106, G 272-52, LTT 873, NLTT 5358, WD 0133-116[7]
Database references
SIMBAD	data

This DA-class white dwarf is the surviving core of a red giant star that ceased nuclear fusion while shedding its outer envelope. It has a (presumably) homogeneous core of carbon and oxygen, a relatively thin outer envelope of hydrogen, and a helium mantle. The object has 65% of the mass of the Sun, with 1.2% of the Sun's radius. It is radiating 0.3% of the luminosity of the Sun at an effective temperature of 12,281 K. Ross 548 is spinning with a period of ~38 hours.^[6] The dominant pulsation mode of this object has a period of 213.1326 seconds. It has up to 11 known pulsation modes in total.^[3]