KIC 7582608: a new Kepler roAp star with frequency variability

Holdsworth, D.L.; Smalley, B.; Kurtz, D.W.; Southworth, J.; Cunha, M.S.; Clubb, K.I.

doi:10.1051/epjconf/201510106033

KIC 7582608: a new Kepler roAp star with frequency variability

Holdsworth, D.L.; Smalley, B.; Kurtz, D.W.; Southworth, J.; Cunha, M.S.; Clubb, K.I.

Authors

D.L. Holdsworth

Barry Smalley b.smalley@keele.ac.uk

D.W. Kurtz

Dr John Taylor j.k.taylor@keele.ac.uk

M.S. Cunha

K.I. Clubb

Abstract

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 181.7324d-1 (P = 7.9 min) with an amplitude of 1.45 mmag, and low frequency rotational modulation corresponding to a period of 20.4339 d. Spectral analysis confirms the Ap nature of the target, with characteristic lines of rare earth elements present. From our spectral observations we derive a lower limit on the mean magnetic field modulus of <B> =3.05 ± 0.23 kG. Long Cadence Kepler observations show a frequency quintuplet split by the rotational period of the star, typical for an oblique pulsator. We suggest the star is a quadrupole pulsator with a geometry such that i ~ 66° and ß ~ 33°. We detect frequency variations of the pulsation in both the WASP and Kepler data sets on many time scales. Linear, non-adiabatic stability modelling allows us to constrain a region on the HR diagram where the pulsations are unstable, an area consistent with observations.

Presentation Conference Type	Poster
Conference Name	The Space Photometry Revolution – CoRoT Symposium 3, Kepler KASC-7 Joint Meeting
Conference Location	Toulouse, France
Start Date	Jul 6, 2014
End Date	Jul 11, 2014
Publicly Available Date	May 26, 2023
Publisher	Società Italiana di Fisica
Series Title	EPJ Web of Conferences
DOI	https://doi.org/10.1051/epjconf/201510106033
Publisher URL	http://dx.doi.org/10.1051/epjconf/201510106033
Additional Information	POSTER SESSION