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Related papers: Mode identification of Pulsating White Dwarfs usin…

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We present a first analysis of the g-mode oscillation spectrum for the white dwarf (WD) primary of GW Lib, a faint cataclysmic variable (CV). Stable periodicities have been observed from this WD for a number of years, but their…

Astrophysics · Physics 2009-11-10 Dean M. Townsley , Phil Arras , Lars Bildsten

We report on the detection of pulsations in the far ultraviolet (hereafter FUV) light curves of PG1219+534, PG1605+072, and PG1613+426 obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) in time-tagged mode (TTAG). Exposures of…

Astrophysics · Physics 2009-11-11 Kuassivi , A. Bonanno , R. Ferlet

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

We present an asteroseismic analysis of the helium atmosphere white dwarf (a DBV) recently found in the field of view of the Kepler satellite. We analyze the 5-mode pulsation spectrum that was produced based on one month of high cadence…

Solar and Stellar Astrophysics · Physics 2015-05-30 Agnés Bischoff-Kim , Roy H. Østensen

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

The {\sl TESS} space mission has recently demonstrated its great potential to discover new pulsating white dwarf and pre-white dwarf stars, and to detect periodicities with high precision in already known white-dwarf pulsators. We report…

We present time-series VLT spectroscopy and NTT photometry of the cataclysmic variable SDSS J220553.98+115553.7, which contains a pulsating white dwarf. We determine a spectroscopic orbital period of 82.825 +/- 0.089 min from velocity…

Astrophysics · Physics 2009-11-13 John Southworth , D W Townsley , B T Gaensicke

The main goal of this project is to search for p-mode oscillations in a selected sample of DA white dwarfs near the blue edge of the DAV (g-mode) instability strip, where the p-modes should be excited following theoretical models. A set of…

Solar and Stellar Astrophysics · Physics 2015-05-20 Roberto Silvotti , Gilles Fontaine , Mike Pavlov , Tom R. Marsh , Vik S. Dhillon , Stuart P. Littlefair , Fedor Getman

Non-radial pulsations have been identified in a number of accreting white dwarfs in cataclysmic variables. These stars offer insight into the excitation of pulsation modes in atmospheres with mixed compositions of hydrogen, helium, and…

Dwarf novae are a subset of cataclysmic variables that accrete material intermittently in short-duration outbursts with sometimes long quiescent intervals in between. During the quiescent state, the white dwarf (WD) photosphere may be…

Solar and Stellar Astrophysics · Physics 2025-12-25 Praphull Kumar , Dean M. Townsley

The possible existence of warm ($T_{\rm eff}\sim19\,000$ K) pulsating DA white dwarf (WD) stars, hotter than ZZ Ceti stars, was predicted in theoretical studies more than 30 yr ago. However, to date, no pulsating warm DA WD has been…

We present the detection of low-amplitude, long-period g-modes in two individual sdBV stars which are known to be p-mode pulsators. Only few of these hybrid objects, showing both p- and g-modes, are known today. We resolve the g-mode domain…

We report the detection of periodic variations on the T_eff ~32 000 K DA white dwarf star HE 1017-1352. We obtained time series photometry using the 4.1 m SOAR telescope on three separate nights for a total of 16.8 h. From the frequency…

Solar and Stellar Astrophysics · Physics 2020-06-10 Alejandra D. Romero , L. Antunes Amaral , S. O. Kepler , L. Fraga , D. Kurtz , H. Shibahashi

In the first spectroscopic campaign for a PG 1716 variable (or long-period pulsating subdwarf B star), we succeeded in detecting velocity variations due to g-mode pulsations at a level of 1.0-1.5 km/s.The observations were obtained during…

We investigate the potential of multi-colour photometry for partial mode identification in both long- and short-period variable subdwarf B stars. The technique presented is based on the fact that the frequency dependence of an oscillation's…

Astrophysics · Physics 2009-11-11 S. K. Randall , G. Fontaine , P. Brassard , P. Bergeron

We present the results of the asteroseismological analysis of two rich DAVs, G38-29 and R808, recent targets of the Whole Earth Telescope. 20 periods between 413 s and 1089 s were found in G38-29's pulsation spectrum, while R808 is an even…

Solar and Stellar Astrophysics · Physics 2010-02-09 A. Bischoff-Kim

We have acquired new time series photometry of the two pulsating DB white dwarf stars KUV 05134+2605 and PG 1654+160 with the Whole Earth Telescope. Additional single-site photometry is also presented. We use all these data plus all…

Astrophysics · Physics 2009-11-07 G. Handler

The pulsating hydrogen atmosphere white dwarf star G 117-B15A has been observed since 1974. Its main pulsation period at 215.19738823(63) s, observed in optical light curves, varies by only (5.12+/-0.82)x10^{-15} s/s and shows no glitches,…

We present follow-up time-series photometric observations that confirm and extend the results of the significant discovery made by Barlow et al.(2008) that the Hot DQ white dwarfs SDSS J220029.08-074121.5 and SDSS J234843.30-094245.3 are…

Solar and Stellar Astrophysics · Physics 2015-05-13 P. Dufour , E. M. Green , G. Fontaine , P. Brassard , M. Francoeur , M. Latour

This paper examines the mode identification and presents pulsation models for FG Vir, for which 24 frequencies have been detected. Histograms of the frequency spacings show peaks which are identified with adjacent radial orders and…

Astrophysics · Physics 2007-05-23 M. Breger , A. A. Pamyatnykh , H. Pikall , R. Garrido