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@article{1406897, author = {Paunzen, Ernst and Huemmerich, Stefan and Bernhard, Klaus and Walczak, Przemek}, article_location = {Oxford}, article_number = {2}, doi = {http://dx.doi.org/10.1093/mnras/stx591}, keywords = {stars:activity; stars:individual: HD 123255; stars:variables:delta Scuti}, language = {eng}, issn = {0035-8711}, journal = {Monthly Notices of the Royal Astronomical Society}, title = {K2 observations of 95 Vir: delta Scuti pulsations in a chromospherically active star}, volume = {468}, year = {2017} }
TY - JOUR ID - 1406897 AU - Paunzen, Ernst - Huemmerich, Stefan - Bernhard, Klaus - Walczak, Przemek PY - 2017 TI - K2 observations of 95 Vir: delta Scuti pulsations in a chromospherically active star JF - Monthly Notices of the Royal Astronomical Society VL - 468 IS - 2 SP - 2017-2023 EP - 2017-2023 PB - OXFORD UNIV PRESS SN - 00358711 KW - stars:activity KW - stars:individual: HD 123255 KW - stars:variables:delta Scuti N2 - We have searched for photometric variability in 95 Vir, a fast rotating, chromospherically active early F-type star, which was observed in the framework of Campaign 6 of the Kepler K2 mission. Available literature information on 95 Vir was procured, and well-established calibrations were employed to verify the derived astrophysical parameters. We have investigated the location of our target star in the M-Bol versus log T-eff diagram, which provides information on the evolutionary status. We have discussed our results in detail, drawing on literature information and the theoretical predictions of state-of-the-art pulsation models, with the aim of unravelling the underlying variability mechanisms. From an analysis of 3400 long-cadence measurements, we have identified two main frequencies and several harmonics in our target star. We attribute the main frequency, f1 = 9.537 28 d(-1), to delta Scuti pulsations. The origin of the secondary signal, f2 = 1.071 29 d(-1), is less clear. We have investigated three possible interpretations of the low-frequency variation: binarity, pulsation and rotational modulation. Current evidence favours an interpretation of f 2 as a signature of the rotational period caused by the presence of cool star-spots, which goes along well with the observed chromospheric activity. However, phase-resolved spectroscopy is needed to verify this assumption. We briefly consider other chromospherically active delta Scuti stars that have been presented in the literature. A search for star-spot-induced photometric variability in these objects might be of great interest, as well as an investigation of the interplay between chromospheric and pulsational activity. ER -
PAUNZEN, Ernst, Stefan HUEMMERICH, Klaus BERNHARD and Przemek WALCZAK. K2 observations of 95 Vir: delta Scuti pulsations in a chromospherically active star. \textit{Monthly Notices of the Royal Astronomical Society}. Oxford: OXFORD UNIV PRESS, 2017, vol.~468, No~2, p.~2017-2023. ISSN~0035-8711. Available from: https://dx.doi.org/10.1093/mnras/stx591.
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