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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 ...

The Dust Cloud Around The White Dwarf G 29-38. II. Spectrum From 5 To 40 Mu M And Mid-Infrared Photometric Variability

Reach, William T.; Lisse, Carey; von Hippel, Ted; Mullally, Fergal (2009-03)

We model the mineralogy and distribution of dust around the white dwarf G29-39 using the infrared spectrum from 1 to 35 mu m. The spectral model for G29-38 dust combines a wide range of materials based on spectral studies ...

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 ...

Constraining the Surface Inhomogeneity and Settling Times of Metals on Accreting White Dwarfs

Montgomery, M. H.; Thompson, S. E.; von Hippel, Ted (2008-10)

Due to the short settling times of metals in DA white dwarf atmospheres, any white dwarfs with photospheric metals must be actively accreting. It is therefore natural to expect that the metals may not be deposited uniformly ...

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 ...