PG 1159-035 is the prototypical PG 1159 star after which the class of PG 1159 stars was named. It was discovered in the Palomar-Green survey of ultraviolet-excess stellar objects^[6] and, like the other PG 1159 stars, is in transition between being the central star of a planetary nebula and being a white dwarf.^[7]

PG 1159-035

A light curve for GW Virginis, adapted from Winget et al. (1985)[1]
Observation data Epoch J2000.0 (ICRS)      Equinox J2000.0 (ICRS)
Constellation	Virgo
Right ascension	12h 01m 45.9729s[2]
Declination	−03° 45′ 40.6279″[2]
Apparent magnitude (V)	14.9[3]
Astrometry
Proper motion (μ)	RA: −14.213±0.155[2] mas/yr Dec.: −3.260±0.064[2] mas/yr
Parallax (π)	1.8131 ± 0.0821 mas[2]
Distance	1,800 ± 80 ly (550 ± 20 pc)
Details
Mass	0.63[4] M☉
Radius	0.0254 ± 0.005[5] R☉
Luminosity (bolometric)	200[5] L☉
Surface gravity (log g)	7.59[4] cgs
Temperature	136,000[4] K
Other designations
GW Vir, GW Virginis, 2E 2572, WD 1159-034
Database references
SIMBAD	data

The luminosity of PG 1159-035 was observed to vary in 1979,^[8] and it was given the variable star designation GW Vir in 1985.^[9] Variable PG 1159 stars may be called GW Vir stars, or the class may be split into DOV and PNNV stars.^[10][11] The variability of PG 1139-035, like that of other GW Vir stars, arises from non-radial gravity wave pulsations within itself.^[12] Its light curve has been observed intensively by the Whole Earth Telescope over a 264-hour period in March 1989, and over 100 of its vibrational modes have been found in the resulting vibrational spectrum, with periods ranging from 300 to 1,000 seconds.^{[13] [14]}