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We present the results of time-resolved photometry, abundance analysis and Doppler imaging of an Ap star, HD 100357. The {\it TESS} photometry revealed rotational modulation with a period of 1.6279247 days. Upon inspecting the residuals…

The new photometric data on pulsating Ap star HD~27463 obtained recently with the Transiting Exoplanet Survey Satellite (\textit{TESS}) are analysed to search for variability. Our analysis shows that HD~27463 exhibits two types of…

Solar and Stellar Astrophysics · Physics 2019-11-06 V. Khalack , C. Lovekin , D. M. Bowman , O. Kobzar , A. David-Uraz , E. Paunzen , J. Sikora , P. Lenz , O. Kochukhov , D. L. Holdsworth , G. A. Wade

We report the analysis of high-precision space-based photometric and high-resolution spectroscopic observations of HD 180347. The high-quality light curves from the Transiting Exoplanet Survey Satellite (TESS) under sectors 14, 15, and 26…

Solar and Stellar Astrophysics · Physics 2023-07-05 Otto Trust , Lyudmila Mashonkina , Edward Jurua , Peter De Cat , Vadim Tsymbal , Santosh Joshi

The All-Sky Automated Survey for Supernovae (ASAS-SN) provides long baseline (${\sim}4$ yrs) $V-$band light curves for sources brighter than V$\lesssim17$ mag across the whole sky. We produced V-band light curves for a total of ${\sim}61.5$…

In this paper, we present TESS photometry and high-resolution spectra of the short-period Algol EW Boo. We obtained double-lined radial velocities (RVs) from the time-series spectra and measured the effective temperature of the primary star…

Solar and Stellar Astrophysics · Physics 2022-09-20 Hye-Young Kim , Kyeongsoo Hong , Chun-Hwey Kim , Jae Woo Lee , Min-Ji Jeong , Jang-Ho Park , Mi-Hwa Song

HD~63401 is known magnetic chemically peculiar (mCP) star that shows a slow rotation and probably possesses a hydrodynamically stable stellar atmosphere. In the latter case the atomic diffusion mechanism enforced by the magnetic field can…

Solar and Stellar Astrophysics · Physics 2020-03-09 Pavlo Kashko , Viktor Khalack , Oleksandr Kobzar , Dmytro Tvardovskyi , Mathieu Perron-Cormier

We present our discovery of pulsational radial-velocity variations in the cool Ap star HD 75445, an object spectroscopically similar to the bright, rapidly-oscillating Ap (roAp) star gamma Equ. Based on high-resolution time-series…

Astrophysics · Physics 2009-11-13 O. Kochukhov , S. Bagnulo , G. Lo Curto , T. Ryabchikova

We use very precise frequencies of low-degree solar-oscillation modes measured from 4752 days of data collected by the Birmingham Solar-Oscillations Network (BiSON) to derive seismic information on the solar core. We compare these…

We report the identification of 61.45 d^-1 (711.2 mu Hz) oscillations, with amplitudes of 62.6-mu mag, in KIC 4768731 (HD 225914) using Kepler photometry. This relatively bright (V=9.17) chemically peculiar star with spectral type A5 Vp…

Algol ($\beta$ Persei) is the prototypical semi-detached eclipsing binary and a hierarchical triple system. From 2006 to 2010 we obtained 121 high-resolution and high-S/N \'{e}chelle spectra of this object. Spectral disentangling yields the…

Solar and Stellar Astrophysics · Physics 2015-06-04 V. Kolbas , K. Pavlovski , J. Southworth , C. -U. Lee , D. -J. Lee , J. W. Lee , S. -L. Kim , H. -I. Kim , B. Smalley , A. Tkachenko

In this paper we present a high-resolution spectroscopic analysis of the chemically peculiar star HD207561. During a survey programme to search for new roAp stars in the Northern hemisphere, Joshi et al. (2006) observed significant…

Solar and Stellar Astrophysics · Physics 2015-06-05 S. Joshi , E. Semenko , P. Martinez , M. Sachkov , Y. C. Joshi , S. Seetha , N. K. Chakradhari , D. L. Mary , V. Girish , B. N. Ashoka

We present a multi-instrument analysis of the rapidly oscillating Ap (roAp) star HD 42659. We have obtained $B$ photometric data for this star and use these data, in conjunction with TESS observations, to analyse the high-frequency…

Solar and Stellar Astrophysics · Physics 2019-09-25 Daniel L. Holdsworth , Hideyuki Saio , Donald W. Kurtz

We investigate the relation between rotation periods $P_\mathrm{rot}$ and photometric modulation amplitudes $R_\mathrm{per}$ for $\approx 4,000$ Sun-like main-sequence stars observed by Kepler, using $P_\mathrm{rot}$ and $R_\mathrm{per}$…

Solar and Stellar Astrophysics · Physics 2022-07-20 Kento Masuda

The Ap star HD3980 appears to be a promising roAp candidate based on its fundamental parameters, leading us to search for rapid pulsations with the VLT UV-Visual Echelle Spectrograph (UVES). A precise Hipparcos parallax and estimated…

Astrophysics · Physics 2009-11-13 V. G. Elkin , D. W. Kurtz , L. M. Freyhammer , S. Hubrig , G. Mathys

We present the first results from the Transiting Exoplanet Survey Satellite (TESS) on the rotational and pulsational variability of magnetic chemically peculiar A-type stars. We analyse TESS 2-min cadence data from sectors 1 and 2 on a…

A detailed analysis of more than 800 electronic high-resolution spectra of gamma Cas, which were obtained during a time interval of over 6000 days (16.84 yrs) at several observatories, documents the smooth variations in the density and/or…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. Nemravová , P. Harmanec , P. Koubský , A. Miroshnichenko , S. Yang , M. Šlechta , C. Buil , D. Korčáková , V. Votruba

In photometry of $\gamma$ Cas (B0.5 IVe) from the SMEI and BRITE-Constellation satellites, indications of low-order non-radial pulsation have recently been found, which would establish an important commonality with the class of classical Be…

Since the end of 2018, the Transiting Exoplanet Survey Satellite (TESS) has provided stellar photometry to the astronomical community. We have used TESS data to study rotational modulation in the light curves of a sample of chemically…

Solar and Stellar Astrophysics · Physics 2022-10-12 O. Kobzar , V. Khalack , D. Bohlender , G. Mathys , M. E. Shultz , D. M. Bowman , E. Paunzen , C. Lovekin , A. David-Uraz , J. Sikora , P. Lampens , O. Richard

Altair is an A-type star known to have an appreciably oblate shape owing to its very fast rotation (~300 km/s). Despite of numerous publications on this star, its chemical abundances have been scarcely investigated so far, presumably…

Solar and Stellar Astrophysics · Physics 2026-05-22 Yoichi Takeda
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