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Related papers: The Pulsating Pre-White Dwarf Star PG 0122+200

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We present the first results from the MultiSite Spectroscopic Telescope (MSST) observations of the sdBV star PG1605+072. Pulsating sdB stars (also known as EC14026 stars) offer the chance to gain new insights into the formation and…

Astrophysics · Physics 2009-11-10 S. J O'Toole , S. Falter , U. Heber , C. S. Jeffery , S. Dreizler , S. L. Schuh , the MSST+WET teams

Using high-cadence observations from the Zwicky Transient Facility at low Galactic latitudes, we have discovered a new class of pulsating, hot, compact stars. We have found four candidates, exhibiting blue colors ($g-r\leq-0.1$ mag),…

Marsh et al. detected radio and optical pulsations from the binary system AR Scorpii (AR Sco). This system, with an orbital period of 3.56 h, is composed of a cool, low-mass star and a white dwarf with a spin period of 1.95 min. Optical…

High Energy Astrophysical Phenomena · Physics 2019-07-03 L. du Plessis , Z. Wadiasingh , C. Venter , A. K. Harding , S. Chandra , P. J. Meintjies

K2 photometry is suitable for the exploitation of mode variability on short timescales in hot B subdwarf stars, which is important to constrain nonlinear quantities addressed by the stellar theory of high-order perturbation in the future.…

Solar and Stellar Astrophysics · Physics 2023-12-06 Xiao-Yu Ma , Weikai Zong , Jian-Ning Fu , Stéphane Charpinet , Jiaxin Wang , Keyu Xing

We present an analysis of oscillation mode variability in the hot B subdwarf star EPIC~220422705, a new pulsator discovered from $\sim78$~days of {\em K}2 photometry. The high-quality light curves provide a detection of 66 significant…

Solar and Stellar Astrophysics · Physics 2022-07-27 Xiao-Yu Ma , Weikai Zong , Jian-Ning Fu , M. D. Reed , Jiaxin Wang , Stephane Charpinet , Jie Su

We present the results of a nonadiabatic, linear stability analysis of models of very low-mass stars (VLMSs) and brown dwarfs (BDs) during the deuterium burning phase in the center. We find unstable fundamental modes with periods varying…

Astrophysics · Physics 2009-11-10 Francesco Palla , Isabelle Baraffe

We present a detailed spectroscopic analysis of 61 low mass white dwarfs and provide precise atmospheric parameters, masses, and updated binary system parameters based on our new model atmosphere grids and the most recent evolutionary model…

Solar and Stellar Astrophysics · Physics 2015-06-22 A. Gianninas , P. Dufour , Mukremin Kilic , Warren R. Brown , P. Bergeron , J. J. Hermes

PSR J1744-3922 is a binary pulsar exhibiting highly variable pulsed radio emission. We report on a statistical multi-frequency study of the pulsed radio flux variability which suggests that this phenomenon is extrinsic to the pulsar and…

We present new results of a stability analysis of realistic models of post-extreme horizontal branch stars. We find that g-mode instabilities develop in some of these models as a result of a potent epsilon-mechanism associated with the…

Astrophysics · Physics 2009-10-30 S. Charpinet , G. Fontaine , P. Brassard , B. Dorman

PSR J1738+0333 is one of the four millisecond pulsars known to be orbited by a white dwarf companion bright enough for optical spectroscopy. Of these, it has the shortest orbital period, making it especially interesting for a range of…

High Energy Astrophysical Phenomena · Physics 2012-07-11 J. Antoniadis , M. H. van Kerkwijk , D. Koester , P. C. C. Freire , N. Wex , T. M. Tauris , M. Kramer , C. G. Bassa

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…

In this work, we present the theoretically expected rates of pulsation period change for V777 Her (DBV) variable stars. To this end we employ new evolutionary models representative of pulsating DB white dwarf stars computed in a…

Astrophysics · Physics 2009-11-10 A. H. Corsico , L. G. Althaus

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 present results from the high precision timing analysis of the pulsar-white dwarf (WD) binary PSR J1012+5307 using 15 years of multi-telescope data. Observations were performed regularly by the European Pulsar Timing Array (EPTA)…

PSR J1905+0154A is a binary millisecond pulsar located in the globular cluster (GC) NGC 6749. It was discovered in 2004 in a search for pulsars in GCs carried out with the Arecibo 305-m radio telescope. The pulsar has a spin period of 3.2…

The pulsation of white dwarfs provides crucial information on stellar parameters for understanding the atmosphere and interior structure of these stars. In this study, we present a comprehensive statistical analysis of known ZZ Ceti stars…

Solar and Stellar Astrophysics · Physics 2025-11-06 Tianqi Cang , Jiayi Zhang , Jian-Ning Fu , He Zhao , Weikai Zong

Double neutron star (DNS) systems offer excellent opportunities to test gravity theories. We report the timing results of PSR J1901+0658, the first pulsar discovered in the FAST Galactic Plane Pulsar Snapshot (GPPS) Survey. Based on timing…

High Energy Astrophysical Phenomena · Physics 2024-04-25 W. Q. Su , J. L. Han , Z. L. Yang , P. F. Wang , J. P. Yuan , C. Wang , D. J. Zhou , T. Wang , Y. Yan , W. C. Jing , N. N. Cai , L. Xie , J. Xu , H. G. Wang , R. X. Xu , X. P. You

We present observations and analysis of time-series spectroscopy and photometry of the pulsating subdwarf B star PG 1219+534 (KY UMa). Subdwarf B stars are blue horizontal branch stars which have shed most of their hydrogen envelopes.…

Time-resolved observations of a 6' x 6' field, containing the position error boxes of the X-ray source 1WGA J1958.2+3232, were performed in June 1999 with the 91 cm Catania telescope, equipped with a Photon Counting Intensified CCD. The…

Astrophysics · Physics 2007-05-23 M. Uslenghi , P. Bergamini , S. Catalano , L. Tommasi , A. Treves

The white dwarfs are promising laboratories for the study of cosmochronology and stellar evolution. Through observations of the pulsating white dwarfs, we can measure their internal structures and compositions, critical to understanding…