Seismology of the Accreting White Dwarf in GW Librae

We present a first analysis of the g-mode oscillation spectrum for the whitedwarf (WD) primary of GW Lib, a faint cataclysmic variable (CV). Stableperiodicities have been observed from this WD for a number of years, but theirinterpretation as stellar pulsations has been hampered by a lack of theoreticalmodels appropriate to an accreting WD. Using the results of Townsley andBildsten, we construct accreting models for the observed effective temperatureand approximate mass of the WD in GW Lib. We compute g-mode frequencies for arange of accreted layer masses, Macc, and long term accretion rates, . Ifwe assume that the observed oscillations are from l=1 g-modes, then theobserved periods are matched when M ~= 1.02 Msun, Macc ~= 0.31 x 10^-4 Msun and ~= 7.3 x 10^-11 Msun/yr. Much more sensitive observations are needed todiscover more modes, after which we will be able to more accurately measurethese parameters and constrain or measure the WD's rotation rate.Comment: 4 pages, 3 figures; uses emulateapj; Accepted by the Astrophysical Journal Letter