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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 report the discovery of four new pulsating subdwarf B (sdBV) stars from Campaign 7 of the Kepler spacecraft's K2 mission. EPICs 215776487, 217280630, 218366972, and 218717602 are all gravity (g)-mode pulsators and we also detect two…

Solar and Stellar Astrophysics · Physics 2021-09-01 M. D. Reed , A. J. Slayton , A. S. Baran , J. H. Telting , R. H. Ostensen , C. S. Jeffery , M. Uzundag , S. Sanjayan

We analyse the fifth roAp star reported in the Kepler field, KIC 7582608, discovered with the SuperWASP project. The object shows a high frequency pulsation at 181.7324 d$^{-1}$ (P=7.9 min) with an amplitude of 1.45 mmag, and low frequency…

Solar and Stellar Astrophysics · Physics 2015-06-22 Daniel L. Holdsworth , Barry Smalley , Donald W. Kurtz , John Southworth , Margarida S. Cunha , Kelsey I. Clubb

We obtain time-series spectrophotometry observations at the VLT with the aim of partially identifying the dominant oscillation modes in the rapidly pulsating subdwarf B star EC 20338-1925 on the basis of monochromatic amplitude and phase…

Solar and Stellar Astrophysics · Physics 2015-05-19 S. K. Randall , G. Fontaine , P. Brassard , V. Van Grootel

The subdwarf B (sdB) star V391 Peg oscillates in short-period p modes and long-period g modes, making it one of the three known hybrids among sdBs. As a by-product of the effort to measure secular period changes in the p modes due to…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. Schuh , R. Kruspe , R. Lutz , R. Silvotti

V391 Peg (HS2201+2610) is an extreme horizontal branch subdwarf B (sdB) star, it is an hybrid pulsator showing p- and g-mode oscillations, and hosts a 3.2/sini M_Jup planet at an orbital distance of about 1.7 AU. In order to improve the…

Solar and Stellar Astrophysics · Physics 2015-05-19 Roberto Silvotti , Suzanna Randall , Vik S. Dhillon , Tom R. Marsh , Chris D. Savoury , Sonja Schuh , Gilles Fontaine , Pierre Brassard

We have acquired simultaneous high-precision space photometry and radial velocities of the bright hybrid Beta Cep/SPB pulsator Gamma Peg. Frequency analyses reveal the presence of six g modes of high radial order together with eight…

Solar and Stellar Astrophysics · Physics 2015-05-13 G. Handler

Internal magnetic fields are an elusive component of stellar structure. However, they can play an important role in stellar structure and evolution models through efficient angular momentum transport and their impact on internal mixing. We…

Solar and Stellar Astrophysics · Physics 2026-01-14 Jelle Vandersnickt , Vincent Vanlaer , Mathijs Vanrespaille , Conny Aerts

We have observed a complex and continuous change in the integrated pulse profile of PSR B2217+47, manifested as additional components trailing the main peak. These transient components are detected over 6 years at $150$ MHz using the LOw…

We report on a global CCD time-series photometric campaign to decode the pulsations of the nucleus of the planetary nebula NGC1501. The star is hot and hydrogen-deficient, similar to the pre-white-dwarf PG 1159 stars. NGC1501 shows…

We have acquired 65 h of single-site time-resolved CCD photometry of the pulsating DB white dwarf star CBS 114 and 62 h of two-site high-speed CCD photometry of another DBV, PG 1456+103. The pulsation spectrum of PG 1456+103 is complicated…

Astrophysics · Physics 2009-11-07 G. Handler , T. S. Metcalfe , M. A. Wood

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 briefly review progress in developing a pathway to nonlinear astereoseismology, both from theoretical and observational aspects. As predicted by the theory of weak nonlinear interactions between resonant modes, their amplitude and…

Solar and Stellar Astrophysics · Physics 2023-02-07 Weikai Zong , Stéphane Charpinet , Gérard Vauclair , Jian-Ning Fu , Xiao-Yu Ma

The recently discovered subdwarf B (sdB) pulsator KIC11558725 features a rich g-mode frequency spectrum, with a few low-amplitude p-modes at short periods, and is a promising target for a seismic study aiming to constrain the internal…

One of the largest uncertainties in stellar structure and evolution theory is the transport of angular momentum in the stellar interiors. Asteroseismology offers a powerful tool for measuring the internal rotation frequencies of pulsating…

Solar and Stellar Astrophysics · Physics 2022-11-30 May G. Pedersen

We suggest that high-order g modes can be used as a probe of the internal magnetic field of SPB (slowly pulsating B) stars. The idea is based on earlier work by the authors which analytically investigated the effect of a vertical magnetic…

Astrophysics · Physics 2009-11-11 S. S. Hasan , J. -P. Zahn , J. Christensen-Dalsgaard

Slowly pulsating B stars (SPB) and $\gamma$ Dor stars pulsate in high-order gravity (g-) modes. The frequencies of g-modes are sensitive to the detailed structure and evolution history of stars having convective cores. Receding convective…

Solar and Stellar Astrophysics · Physics 2015-12-09 Ehsan Moravveji

Context. There exist few variability studies of stars in the region in the Hertzsprung-Russell diagram between the A and B-star pulsational instability strips. With the aid of the high precision continuous measurements of the CoRoT space…

Solar and Stellar Astrophysics · Physics 2015-05-30 P. Degroote , B. Acke , R. Samadi , C. Aerts , D. W. Kurtz , A. Noels , A. Miglio , J. Montalban , S. Bloemen , A. Baglin , F. Baudin , C. Catala , E. Michel , M. Auvergne

We present a detailed single-pulse analysis for PSR B1929+10 based on observations with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The main pulse and interpulse are found to be modulated with a periodicity of $\sim12$…

High Energy Astrophysical Phenomena · Physics 2021-03-24 F. F. Kou , W. M. Yan , B. Peng , J. G. Lu , K. Liu , C. M. Zhang , R. G. Strom , L. Wang , J. P. Yuan , Rai Yuen , Y. Z. Yu , J. M. Yao , B. Liu , J. Yan , P. Jiang , C. J. Jin , D. Li , L. Qian , Y. L. Yue , Y. Zhu