HST and Optical Data Reveal White Dwarf Cooling, Spin and Periodicities in GW Librae 3-4 Years after Outburst

Abstract

Since the large amplitude 2007 outburst which heated its accreting, pulsating white dwarf, the dwarf nova system GW Librae has been cooling to its quiescent temperature. Our Hubble Space Telescope ultraviolet spectra combined with ground-based optical coverage during the 3rd and 4th year after outburst show that the fluxes and temperatures are still higher than quiescence (T=19,700K and 17,300K vs 16,000K pre-outburst for a log g=8.7 and d=100 pc). The K{wd} of 7.6+/-0.8 km/s determined from the CI1463 absorption line, as well as the gravitational redshift implies a white dwarf mass of 0.79+/-0.08 Msun. The widths of the UV lines imply a white dwarf rotation velocity vsin i of 40 km/s and a spin period of 209 s (for an inclination of 11 deg and a white dwarf radius of 7x10^{8} cm). Light curves produced from the UV spectra in both years show a prominent multiplet near 290 s, with higher amplitude in the UV compared to the optical, and increased amplitude in 2011 vs 2010. As the presence of this set of periods is intermittent in the optical on weekly timescales, it is unclear how this relates to the non-radial pulsations evident during quiescence.

36 pages, 15 figures; Astrophysical Journal, 2012, 753

References in corpus (7)

• Post-common-envelope binaries from SDSS. XI: The white dwarf mass distributions of CVs and pre-CVs
• Pulsational Instabilities in Accreting White Dwarfs
• Dynamical constraints on the component masses of the cataclysmic variable WZ Sge
• HST/STIS Spectroscopy and Modeling of the Long Term Cooling of WZ Sagittae following the July 2001 Outburst
• ULTRACAM observations of two accreting white dwarf pulsators
• Two new accreting, pulsating white dwarfs: SDSS J1457+51 and BW Sculptoris
• SDSS J080434.20+510349.2: Cataclysmic Variable Witnessing the Instability Strip?

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