Holdsworth, DL and Smalley, B and Kurtz, DW and Southworth, J and Cunha, MS and Clubb, KI (2015) KIC 7582608: a new Kepler roAp star with frequency variability. EPJ Web of Conferences: The Space Photometry Revolution – CoRoT Symposium 3, Kepler KASC-7 Joint Meeting, 101. ISSN 2100-014X

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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 β ~ 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.

Item Type: Article
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Related URLs:
Depositing User: Symplectic
Date Deposited: 14 Jun 2016 09:37
Last Modified: 14 Jun 2016 11:12
URI: http://eprints.keele.ac.uk/id/eprint/1849

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