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The Physics of Crystallization from Globular Cluster White Dwarf Stars in NGC 6397

Winget, D. E.; Kepler, S. O.; Campos, Fabiola; Montgomery, M. H.; Girardi, Leo; Bergeron, P.; Williams, Kurtis (2009-03)

We explore the physics of crystallization in the deep interiors of white dwarf (WD) stars using the color-magnitude diagram and luminosity function constructed from proper- motion cleaned Hubble Space Telescope photometry ...

SDSS J142625.71+575218.3: A Prototype for A New Class of Variable White Dwarf

Montgomery, M. H.; Williams, Kurtis A.; Winget, D. E.; Dufour, Patrick; DeGennaro, Steven; Liebert, James (2008-05)

We present the results of a search for pulsations in six of the recently discovered carbon-atmosphere white dwarf ("hot DQ") stars. On the basis of our theoretical calculations, the star SDSS J142625.71 + 575218.3 is the ...

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). ...

White Dwarfs In Ngc6397 And M4: Constraints On The Physics Of Crystallization

Winget, D. E.; Montgomery, M. H.; Kepler, S. O.; Campos, F.; Bergeron, P. (2010-08)

We explore the physics of crystallization in the dense Coulomb plasma of the deep interiors of white dwarf stars using the color-magnitude diagram and luminosity function constructed from Hubble Space Telescope photometry ...

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 ...

Creating White Dwarf Photospheres In The Laboratory

Falcon, R. E.; Rochau, G. A.; Bailey, J. E.; Ellis, J. L.; Montgomery, M. H.; Winget, D. E.; Gomez, M. R.; Leeper, R. J. (2010-08)

We present a preliminary report from the laboratory astrophysics experiments to create macroscopic (similar to 19 cm(3)) hydrogen-plasmas with white dwarf (WD) photospheric conditions (i.e., temperature, electron density). ...

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, ...