J 2017

K2 observations of 95 Vir: delta Scuti pulsations in a chromospherically active star

PAUNZEN, Ernst, Stefan HUEMMERICH, Klaus BERNHARD a Przemek WALCZAK

Základní údaje

Originální název

K2 observations of 95 Vir: delta Scuti pulsations in a chromospherically active star

Autoři

PAUNZEN, Ernst (40 Rakousko, garant, domácí), Stefan HUEMMERICH (276 Německo), Klaus BERNHARD (40 Rakousko) a Przemek WALCZAK (616 Polsko)

Vydání

Monthly Notices of the Royal Astronomical Society, Oxford, OXFORD UNIV PRESS, 2017, 0035-8711

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10308 Astronomy

Stát vydavatele

Velká Británie a Severní Irsko

Utajení

není předmětem státního či obchodního tajemství

Impakt faktor

Impact factor: 5.194

Kód RIV

RIV/00216224:14310/17:00099898

Organizační jednotka

Přírodovědecká fakulta

DOI

UT WoS

000399429600059

Klíčová slova anglicky

stars:activity; stars:individual: HD 123255; stars:variables:delta Scuti

Štítky

Příznaky

Mezinárodní význam, Recenzováno
Změněno: 6. 4. 2018 10:50, Ing. Nicole Zrilić

Anotace

V originále

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.