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Related papers: Understanding the Cool DA White Dwarf, G29-38

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We present optical spectroscopy and near-infrared photometry of 57 faint ($g= 19-22$) high proper motion white dwarfs identified through repeat imaging of $\approx3100$ square degrees of the Sloan Digital Sky Survey footprint by Munn et al.…

Solar and Stellar Astrophysics · Physics 2016-09-07 Kyra Dame , A. Gianninas , Mukremin Kilic , Jeffrey A. Munn , Warren R. Brown , Kurtis A. Williams , Ted von Hippel , Hugh C. Harris

We present results from a search for short time-scale white dwarf variability using \texttt{gPhoton}, a time-tagged database of \textit{GALEX} photon events and associated software package. We conducted a survey of $320$ white dwarf stars…

We carried out a spectroscopic investigation of single lined white dwarfs (WDs) in double degenerate (DD) systems and discuss their binary evolution. Simulated spectra of the Halpha region are used to derive upper limits on the temperature…

Solar and Stellar Astrophysics · Physics 2009-07-22 S. Weston , R. Napiwotzki

We present a spectro-photometric analysis of 2880 cool white dwarfs within 100 pc of the Sun and cooler than Teff = 10,000 K, with grizy Pan-STARRS photometry and Gaia trigonometric parallaxes available. We also supplement our data sets…

Solar and Stellar Astrophysics · Physics 2022-12-28 Alexandre Caron , Pierre Bergeron , Simon Blouin , Sandy K. Leggett

Axions are the natural consequence of the introduction of the Peccei-Quinn symmetry to solve the strong CP problem. All the efforts to detect such elusive particles have failed up to now. Nevertheless, it has been recently shown that the…

Solar and Stellar Astrophysics · Physics 2015-05-18 J. Isern , E. García-Berro , L. G. Althaus , A. H. Córsico

In this paper we demonstrate how pulsating white dwarfs can be used as an astrophysical laboratory for empirically constraining convection in these stars. We do this using a technique for fitting observed non-sinusoidal light curves, which…

Astrophysics · Physics 2009-11-13 M. H. Montgomery

We present new cooling models for carbon-oxygen white dwarfs with both H- and He-atmospheres, covering the whole relevant mass range, to extend our updated BaSTI (a Bag of Stellar Tracks and Isochrones) stellar evolution archive. They have…

Solar and Stellar Astrophysics · Physics 2021-12-22 Maurizio Salaris , Santi Cassisi , Adriano Pietrinferni , Sebastian Hidalgo

We demonstrate that plasmon neutrinos are the dominant form of energy loss in model white dwarf stars down to T_eff ~ 25,000 K, depending on the stellar mass. The lower end of this range overlaps the observed temperatures for the V777 Her…

Astrophysics · Physics 2009-11-10 D. E. Winget , D. J. Sullivan , T. S. Metcalfe , S. D. Kawaler , M. H. Montgomery

We present time-resolved spectrophotometry of the pulsating DA white dwarf G 29-38. As in previous broad-band photometry, the light curve shows the presence of a large number of periodicities. Many of these are combination frequencies,…

Astrophysics · Physics 2009-10-31 M. H. van Kerkwijk , J. C. Clemens , Y. Wu

White dwarfs are the burnt out cores of Sun-like stars and are the final fate of 97% of all stars in our Galaxy. The internal structure and composition of white dwarfs are hidden by their high gravities, which causes all elements, apart…

As a result of competing physical mechanisms, the atmospheric composition of white dwarfs changes throughout their evolution, a process known as spectral evolution. Because of the ambiguity of their atmospheric compositions and the…

Solar and Stellar Astrophysics · Physics 2019-06-19 Simon Blouin , Patrick Dufour , Christian Thibeault , Nicole F. Allard

We employ a state-of-the-art asteroseismological model of G117-B15A, the archetype of the H-rich atmosphere (DA) white dwarf pulsators (also known as DAV or ZZ Ceti variables), and use the most recently measured value of the rate of period…

In the light of the recent and unexpected discovery of a brand new type of white dwarfs, those with carbon-dominated atmospheres, we examine the asteroseismological potential of such stars. The motivation behind this is based on the…

Astrophysics · Physics 2009-11-13 G. Fontaine , P. Brassard , P. Dufour

The helium-atmosphere (DB) white dwarfs are commonly thought to be the descendants of the hotter PG1159 stars, which initially have uniform He/C/O atmospheres. In this evolutionary scenario, diffusion builds a pure He surface layer which…

Astrophysics · Physics 2007-05-23 T. S. Metcalfe , R. E. Nather , T. K. Watson , S. -L. Kim , B. -G. Park , G. Handler

We present the first detailed photometric and spectroscopic study of the white dwarfs (WDs) in the field of the ~225 Myr old (log tau_cl = 8.35) open cluster NGC 1039 (M34) as part of the ongoing Lick-Arizona White Dwarf Survey. Using…

Astrophysics · Physics 2008-05-22 Kate H. R. Rubin , Kurtis A. Williams , M. Bolte , Detlev Koester

Results are presented from the first detailed spectroscopic observations of the recently identified intermediate polar RXJ0028.8+5917/V709 Cas. The study of the emission line radial velocities allows us to remove the uncertainties on the…

Astrophysics · Physics 2009-11-06 J. M. Bonnet-Bidaud , M. Mouchet , D. de Martino , G. Matt , C. Motch

Ultra-cool white dwarfs are among the oldest stellar remnants in the Universe. Their efficient gravitational settling and low effective temperatures are responsible for the smooth spectra they exhibit. For that reason, it is not possible to…

Solar and Stellar Astrophysics · Physics 2020-04-08 M. C. Lam , N. C. Hambly , N. Lodieu , S. Blouin , E. J. Harvey , R. J. Smith , M. C. Galvez-Ortiz , Z. H. Zhang

We consider the pulsational properties of white dwarf star models with temperatures appropriate for the ZZ Ceti instability strip and with masses large enough that they should be substantially crystallized. Our work is motivated by the…

Astrophysics · Physics 2009-10-31 M. H. Montgomery , D. E. Winget

We have paired the Second Data Release of the Large Area Survey of the UKIRT Infrared Deep Sky Survey with the Fifth Data Release of the Sloan Digital Sky Survey to identify ten cool white dwarf candidates, from their photometry and…

Astrophysics · Physics 2014-11-18 N. Lodieu , S. K. Leggett , P. Bergeron , A. Nitta

Using a new grid of models of cooling white dwarfs, we calculate isochrones and luminosity functions in the Johnson-Kron/Cousins and HST filter sets for systems containing old white dwarfs. These new models incorporate a non-grey atmosphere…

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