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Related papers: Eleven New DAVs from the Sloan Survey

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Using photometric selection criteria, and in a final step visual inspection of spectra, we find 65 DQ white dwarfs in the Data Release 4 of the Sloan Digital Sky Survey. 37 of these are new identifications, three more are reclassified DQ…

Astrophysics · Physics 2009-11-11 D. Koester , S. Knist

We present the results of our survey searching for new white dwarf pulsators for observations by the TESS space telescope. We collected photometric time-series data on 14 white dwarf variable-candidates at Konkoly Observatory, and found two…

Solar and Stellar Astrophysics · Physics 2018-07-04 Zs. Bognár , Cs. Kalup , Á. Sódor , S. Charpinet , J. J. Hermes

We present a novel method to detect variable astrophysical objects and transient phenomena using anomalous excess scatter in repeated measurements from public catalogs of Gaia DR2 and Zwicky Transient Facility (ZTF) DR3 photometry. We first…

We present the first asteroseismological study for 42 massive ZZ Ceti stars based on a large set of fully evolutionary carbon$-$oxygen core DA white dwarf models characterized by a detailed and consistent chemical inner profile for the core…

Solar and Stellar Astrophysics · Physics 2015-06-17 A. D. Romero , S. O. Kepler , A. H. Córsico , L. G. Althaus , L. Fraga

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…

SDSS (DR1 and DR2) has recently proposed 7 new DO white dwarfs as well as 6 new PG1159 stars. This is a significant increase in the known number of DOs and PG1159 stars. Our spectral analyses provide stellar parameters which can then be…

Astrophysics · Physics 2016-02-09 S. D. Huegelmeyer , S. Dreizler , K. Werner , A. Nitta , S. J. Kleinman , J. Krzesinski

We report on the identification of 22 new cool DO-type white dwarfs (WD) detected in Data Release 10 (DR10) of the Sloan Digital Sky Survey (SDSS). Among them, we found one more member of the so-called hot-wind DO WDs, which show ultrahigh…

Solar and Stellar Astrophysics · Physics 2014-12-10 N. Reindl , T. Rauch , K. Werner , S. O. Kepler , B. T. Gänsicke , N. P. Gentile Fusillo

We report the discovery of the second and third pulsating extremely low mass white dwarfs (WDs), SDSS J111215.82+111745.0 (hereafter J1112) and SDSS J151826.68+065813.2 (hereafter J1518). Both have masses < 0.25 Msun and effective…

We report the discovery of the first identified pulsating DA white dwarf in the field of the Kepler mission, WD J1916+3938 (Kepler ID 4552982). This ZZ Ceti star was first identified through ground-based, time-series photometry, and…

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 have obtained Hubble Space Telescope UV spectra of the white dwarf in GW Lib, the only known non-radially pulsating white dwarf in a cataclysmic variable, and the first known DAZQ variable. The UV light curve reveals large amplitude…

Astrophysics · Physics 2009-11-07 P. Szkody , B. Gansicke , S. B. Howell , E. Sion

We report on the spectroscopic confirmation of 68 new bright ($G=13.5-17.2$ mag) and blue (pre-)white dwarfs (WDs). This finding has allowed us to almost double the number of the hottest ($T_{\mathrm{eff}} \geq 60$kK) known WDs brighter…

There are now four dwarf novae known with white dwarf primaries that show large amplitude non-radial oscillations of the kind seen in ZZ Cet stars. We compare the properties of these stars and point out that by the end of the Sloan Digital…

Astrophysics · Physics 2007-05-23 Brian Warner , Patrick A. Woudt

For some years now, we have been gathering optical spectra of DA white dwarfs in an effort to study and define the empirical ZZ Ceti instability strip. However, we have recently expanded this survey to include all the DA white dwarfs in the…

Astrophysics · Physics 2009-07-22 A. Gianninas , P. Bergeron , M. T. Ruiz

We present time-series photometry of 31 massive DA white dwarfs with $M\gtrsim 0.9~M_\odot$ within the ZZ Ceti instability strip from the Montreal White Dwarf Database 100 pc sample. The majority of the targets had no previous time-series…

Carbon stars and DZ white dwarfs are two types of rare objects in the Galaxy. In this paper, we have applied the label propagation algorithm to search for these two types of stars from Data Release Eight (DR8) of the Sloan Digital Sky…

Instrumentation and Methods for Astrophysics · Physics 2013-12-25 Jianmin Si , Ali Luo , Yinbi Li , Jiannan Zhang , Peng Wei , Yihong Wu , Fuchao Wu , Yongheng Zhao

As established by ground based surveys, white dwarfs with hydrogen atmospheres pulsate as they cool across the temperature range, $12500\,\mathrm{K} \gtrsim T_{\mathrm{eff}} \gtrsim 10800\,\mathrm{K}$. Known as DAVs or ZZ Ceti stars, their…

Solar and Stellar Astrophysics · Physics 2018-08-22 Jing Luan , Peter Goldreich

The spectroscopic sky survey carried out by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) provides the largest stellar spectra library in the world until now. A large number of new DA white dwarfs had been…

Solar and Stellar Astrophysics · Physics 2017-10-04 Jie Su , Jianning Fu , Guifang Lin , Fangfang Chen , Pongsak Khokhuntod , Chunqian Li

We present a large bank of chemical profiles and pulsation periods suited for asteroseismological studies of ZZ Ceti (or DAV) variable stars. Our background equilibrium DA white dwarf models are the result of fully evolutionary computations…

Solar and Stellar Astrophysics · Physics 2012-04-30 Alejandra D. Romero , Alejandro H. Córsico , Leandro G. Althaus , Marcelo M. Miller Bertolami

We report the results of our search for pulsating subdwarf B stars in Full Frame Images, sampled at 30 min cadence and collected during Year 1 of the TESS mission. Year 1 covers most of the southern ecliptic hemisphere. The sample of…

Solar and Stellar Astrophysics · Physics 2020-11-09 S. K. Sahoo , A. S. Baran , S. Sanjayan , J. Ostrowski