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Limits On Planets Around Pulsating White Dwarf Stars

Mullally, Fergal; Winget, D. E.; Degennaro, Steven; Jeffery, Elizabeth; Thompson, Susan E.; Chandler, Dean; Kepler, S. O. (2008-03)

We present limits on planetary companions to pulsating white dwarf stars. A subset of these stars exhibit extreme stability in the period and phase of some of their pulsation modes; a planet can be detected around such a ...

Measuring The Evolutionary Rate Of Cooling Of ZZ Ceti

Mukadam, Anjum S.; Bischoff-Kim, Agnes; Fraser, Oliver; Corsico, A. H.; Montgomery, Michael H.; Kepler, S. O.; Romero, A. D.; Winget, D. E.; Hermes, J. J.; Riecken, T. S.; Kronberg, M. E.; Winget, K. I.; Falcon, Ross E.; Chandler, Dean W.; Kuehne, J. W.; Sullivan, Denis J.; Reaves, D.; von Hippel, Ted; Mullally, Fergal; Shipman, H.; Thompson, Susan E.; Silvestri, N. M.; Hynes, Robert I. (2013-07)

We have finally measured the evolutionary rate of cooling of the pulsating hydrogen atmosphere (DA) white dwarf ZZ Ceti (Ross 548), as reflected by the drift rate of the 213.13260694 s period. Using 41 yr of time-series ...

A New Timescale For Period Change In The Pulsating DA White Dwarf WD 0111+0018

Hermes, J. J.; Montgomery, Michael H.; Mullally, Fergal; Winget, D. E.; Bischoff-Kim, Agnes (2013-03)

We report the most rapid rate of period change measured to date for a pulsating DA (hydrogen atmosphere) white dwarf (WD), observed in the 292.9 s mode of WD0111+0018. The observed period change, faster than 10(-12) s ...

A New ZZ Ceti White Dwarf Pulsator: G30-20

Mukadam, Anjum S.; Kepler, S. O.; Winget, D. E.; Bergeron, P. (2002-11)

We report the discovery of a new hydrogen atmosphere variable white dwarf (DAV; ZZ Ceti), G30-20, a high-amplitude, long-period pulsator. The Fourier transform of its light curve shows power around 1050-1125 s. We suspect ...

White Dwarf Luminosity And Mass Functions From Sloan Digital Sky Survey Spectra

DeGennaro, Steven; von Hippel, Ted; Winget, D. E.; Kepler, S. O.; Nitta, Atsuko; Koester, Detlev; Althaus, Leandro (2008-01)

We present the first phase in our ongoing work to use Sloan Digital Sky Survey (SDSS) data to create separate white dwarf (WD) luminosity functions (LFs) for two or more different mass ranges. In this paper, we determine ...

Photometric Variability In A Warm, Strongly Magnetic Dq White Dwarf, SDSS J103655.39+652252.2

Williams, Kurtis A.; Winget, D. E.; Montgomery, Michael H.; Dufour, Patrick; Kepler, S. O.; Hermes, J. J.; Falcon, Ross E.; Winget, K. I.; Bolte, Michael; Rubin, Kate H. R.; Liebert, James (2013-06)

We present the discovery of photometric variability in the DQ white dwarf SDSS J103655.39+652252.2 (SDSS J1036+6522). Time-series photometry reveals a coherent monoperiodic modulation at a period of 1115.64751(67) s with ...

Two New Tidally Distorted White Dwarfs

Hermes, J. J.; Kilic, Mukremin; Brown, Warren R.; Montgomery, Michael H.; Winget, D. E. (2012-04)

We identify two new tidally distorted white dwarfs (WDs), SDSS J174140.49+652638.7 and J211921.96-001825.8 (hereafter J1741 and J2119). Both stars are extremely low mass (ELM, <= 0.2 M-circle dot)WDs in short-period, ...

Enigmatic Recurrent Pulsational Variability Of The Accreting White Dwarf EQ LYN (Sdss J074531.92+453829.6)

Mukadam, Adam S.; Townsley, D. M.; Szkody, Paula; Gaansicke, B. T.; Southworth, J.; Brockett, T.; Parsons, S.; Hermes, J. J.; Montgomery, M. H.; Winget, D. E.; Harrold, S.; Tovmassian, G.; Zharikov, S.; Drake, A. J.; Henden, A.; Rodriguez-Gil, P.; Sion, E. M.; Zola, S.; Szymanski, T.; Pavlenko, E.; Aungwerojwit, A.; Qian, S. B. (2013-09)

Photometric observations of the cataclysmic variable EQ Lyn (SDSS J074531.92+453829.6), acquired from 2005 October to 2006 January, revealed high-amplitude variability in the range 1166-1290 s. This accreting white dwarf ...

A Gravitational Redshift Determination Of The Mean Mass Of DBA White Dwarfs

Falcon, R. E.; Winget, D. E.; Montgomery, M. H.; Williams, K. A. (2010-08)

We measure apparent velocities (v(app)) of the H alpha and H beta Balmer line cores for 16 helium-dominated white dwarfs (WDs) using optical spectra taken for the European Southern Observatory SN Ia progenitor survey (SPY). ...

Radius Constraints From High-Speed Photometry Of 20 Low-Mass White Dwarf Binaries

Hermes, J. J.; Brown, Warren R.; Kilic, Mukremin; Gianninas, A.; Chote, Paul; Sullivan, Denis J.; Winget, D. E.; Bell, Keaton J.; Falcon, Ross E.; Winget, K. I.; Mason, Paul A.; Harrold, Samuel T.; Montgomery, Michael H. (2014-09)

We carry out high-speed photometry on 20 of the shortest-period, detached white dwarf binaries known and discover systems with eclipses, ellipsoidal variations (due to tidal deformations of the visible white dwarf), and ...