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In this article we present the O-C diagram of the hot subdwarf B pulsating star HS2201+2610 after seven years of observations. A secular increase of the main pulsation period, Pdot=(1.3+-0.1)x10**(-12), is inferred from the data. Moreover,…

We have carried out a detailed asteroseismic analysis of PG 1219+534. Our analysis leads to the identification of the (k,l) indices of nine periods observed in the star PG 1219+534, and to the determination of its structural parameters. The…

Astrophysics · Physics 2009-11-10 S. Charpinet , G. Fontaine , P. Brassard , E. M. Green , P. Chayer

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

Hot subdwarf B (sdB) stars are post-main-sequence stars of high temperature and gravity. Approximately 30$\%$ of sdBs exhibit stable pressure and/or gravity-mode pulsations, which can be used via the timing method to test for companion…

Solar and Stellar Astrophysics · Physics 2025-08-05 Tomomi Otani , A. S. Baran , Lindsay C. Spence , Ted von Hippel , E. Lynum-Lozano , Julia. M. Clark

We present optical high-speed photometry of three millisecond pulsars with low-mass ($< 0.3 M_{\odot}$) white dwarf companions, bringing the total number of such systems with follow-up time-series photometry to five. We confirm the…

In a photometric variability survey of 131 stars with B < 14 mag, we have found four new Delta Scuti stars. We were sensitive to oscillation amplitudes as low as a few mmag. The detection rate of short-period (P < 0.1 d) pulsating variable…

Astrophysics · Physics 2009-11-07 J. L. Sokoloski , Lars Bildsten , R. Chornock , Alexei V. Filippenko

The recently discovered subdwarf B (sdB) pulsator KIC7668647 is one of the 18 pulsating sdB stars detected in the Kepler field. It features a rich g-mode frequency spectrum, with a few low-amplitude p-modes at short periods. We use new…

Solar and Stellar Astrophysics · Physics 2014-11-05 J. H. Telting , A. S. Baran , P. Nemeth , R. H. Ostensen , T. Kupfer , S. Macfarlane , U. Heber , C. Aerts , S. Geier

The subdwarf B star PG1605+072, with an unusually low log g ~ 5.3, shows a high number of non-radial pulsation modes, making it a promising candidate for asteroseismology. This could allow probing the star's interior to gain important…

Solar and Stellar Astrophysics · Physics 2012-03-07 Jan Langfellner , Sonja Schuh , the MSST , WET teams

We report the discovery of a large-amplitude oscillation in the hot subdwarf B star CS 1246 and present multi-colour photometry and time-resolved spectroscopy supporting this discovery. We used the 0.41-m PROMPT array to acquire data in the…

We report seismic analyses of five pulsating subdwarf B (sdBV) stars observed during Kepler's K2 mission, each with a white dwarf companion. We find three of the five to be g-mode-dominated hybrid pulsators. For the other two, we only…

Solar and Stellar Astrophysics · Physics 2025-06-06 M. D. Reed , A. S. Baran , J. H. Telting , R. H. Ostensen , C. S. Jeffery , Y. Gaibor

We report on the detection of pulsations of three pulsating subdwarf B stars observed by the TESS satellite and our results of mode identification in these stars based on an asymptotic period relation. SB 459 (TIC 067584818), SB 815 (TIC…

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

Helium-rich subdwarf B (He-sdB) stars represent a small group of low-mass hot stars with luminosities greater than those of conventional subdwarf B stars, and effective temperatures lower than those of subdwarf O stars. By measuring their…

Solar and Stellar Astrophysics · Physics 2015-05-20 Naslim N. , C. S. Jeffery , N. T. Behara , A. Hibbert

SDSS J111215.82+111745.0 is the second pulsating extremely low-mass white dwarf discovered. Two short-period pulsations, 107.56 and 134.275 s, were detected on this star, which would be the first observed pressure mode ($p$-mode) pulsations…

Solar and Stellar Astrophysics · Physics 2023-02-08 Jie Su , Yan Li

We present photometric and spectroscopic analyses of gravity (g-mode) long-period pulsating hot subdwarf B (sdB) stars. We perform a detailed asteroseismic and spectroscopic analysis of five pulsating sdB stars observed with {\it TESS}…

Hot cluster Horizontal Branch (HB) stars and field subdwarf B (sdB) stars are core helium burning stars that exhibit abundance anomalies that are believed to be due to atomic diffusion. Diffusion can be effective in these stars because they…

Solar and Stellar Astrophysics · Physics 2015-06-03 G. Mathys , S. Hubrig , E. Mason , G. Michaud , M. Schoeller , F. Wesemael

We present the results of a multisite photometric campaign on the pulsating sdB star Balloon 090100001. The star is one of the two known hybrid hot subdwarfs with both long- and short-period oscillations. The campaign involved eight…

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

Among the competing evolution theories for subdwarf-B (sdB) stars is the binary evolution scenario. EC~20117-4014 (=V4640~Sgr) is a spectroscopic binary system consisting of a pulsating sdB star and a late F main-sequence companion…

Solar and Stellar Astrophysics · Physics 2018-06-13 T. Otani , T. Oswalt , A. E. Lynas-Gray , D. Kilkenny , K. Koen , M. Amaral , R. Jordan

The survey phase of the Kepler Mission includes a number of hot subdwarf B (sdB) stars to search for nonradial pulsations. We present our analysis of two sdB stars that are found to be g-mode pulsators of the V1093 Her class. These two…