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]
^
abKawaler, Steven D.; Bradley, Paul A. (1994). "Precision asteroseismology of pulsating PG 1159 stars". The Astrophysical Journal. 427: 415.
Bibcode:
1994ApJ...427..415K.
doi:
10.1086/174152.
^McGraw, J. T.;
Starrfield, S. G.; Liebert, J.; Green, R. (1979). "PG 1159-035: A New, Hot, Non-Da Pulsating Degenerate". IAU Colloq. 53: White Dwarfs and Variable Degenerate Stars: 377.
Bibcode:
1979wdvd.coll..377M.
^Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Perova, N. B. (1985). "The 67th Name-List of Variable Stars". Information Bulletin on Variable Stars. 2681: 1.
Bibcode:
1985IBVS.2681....1K.
^Quirion, P. -O; Fontaine, G.; Brassard, P. (2007). "Mapping the Instability Domains of GW vir Stars in the Effective Temperature-Surface Gravity Diagram". The Astrophysical Journal Supplement Series. 171 (1): 219.
Bibcode:
2007ApJS..171..219Q.
doi:
10.1086/513870.
S2CID122695910.