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Limits Of Perturbative Nonlinear Light Curve Analyses: The Case Of G117-B15A

Montgomery, M. H.; Hermes, J. J.; Winget, D. E. (2010-08)

This poster examines the nonlinear combination frequencies found in the DAV G117-B15A. Using multiple epochs of observations we show that the ratio of the amplitude of the combination frequencies to those of the parent ...

Discovery of an Ultramassive Pulsating White Dwarf

Hermes, J. J.; Kepler, S. O.; Castanheira, Barbara G.; Gianninas, A.; Winget, D. E.; Montgomery, M. H.; Brown, Warren R.; Harrold, Samuel T. (2013-07)

We announce the discovery of the most massive pulsating hydrogen-atmosphere white dwarf (WD) ever discovered, GD 518. Model atmosphere fits to the optical spectrum of this star show it is a 12,030 +/- 210 K WD with a log ...

A Second Case of Outbursts in A Pulsating White Dwarf Observed By Kepler

Hermes, J. J.; Montgomery, M. H.; Bell, Keaton J.; Chote, P.; Gansicke, B. T.; Kawaler, Steven D.; Clemens, J. Christopher; Dunlap, B. H.; Winget, D. E.; Armstrong, D. J. (2015-09)

We present observations of a new phenomenon in pulsating white dwarf stars: large-amplitude outbursts at timescales much longer than the pulsation periods. The cool (T-eff = 11,060 K), hydrogen-atmosphere pulsating white ...

SDSS J184037.78+642312.3: the First Pulsating Extremely Low Mass White Dwarf

Hermes, J. J.; Montgomery, M. H.; Winget, D. E.; Brown, Warren R.; Kilic, Mukremin; Kenyon, Scott J. (2012-05)

We report the discovery of the first pulsating extremely low mass (ELM) white dwarf (WD), SDSS J184037.78+642312.3 (hereafter J1840). This DA (hydrogen-atmosphere) WD is by far the coolest and the lowest-mass pulsating WD, ...