Based on observations made with the Nordic Optical Telescope, operated jointly by Denmark, Finland, Iceland, Norway and Sweden, on the island of La Palma at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias (IAC).
Unusual high-frequency oscillations in the Kepler Scuti star KIC 4840675★
Article first published online: 28 JUN 2012
© 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS
Monthly Notices of the Royal Astronomical Society
Volume 424, Issue 2, pages 1187–1196, August 2012
How to Cite
Balona, L. A., Breger, M., Catanzaro, G., Cunha, M. S., Handler, G., Kołaczkowski, Z., Kurtz, D. W., Murphy, S., Niemczura, E., Paparó, M., Smalley, B., Szabó, R., Uytterhoeven, K., Christiansen, J. L., Uddin, K. and Stumpe, M. C. (2012), Unusual high-frequency oscillations in the Kepler Scuti star KIC 4840675. Monthly Notices of the Royal Astronomical Society, 424: 1187–1196. doi: 10.1111/j.1365-2966.2012.21295.x
- Issue published online: 13 JUL 2012
- Article first published online: 28 JUN 2012
- Accepted 2012 May 11. Received 2012 May 11; in original form 2012 March 29
- binaries: spectroscopic;
- stars: individual: KIC 4840675;
- stars: oscillations;
- stars: variables: δ Scuti
We show that the star KIC 4840675 observed by Kepler is composed of three stars with a rapidly rotating A-type star and two solar-type fainter companions. The A-type star is a δ Scuti variable with a dominant mode and many other modes of lower amplitude, including several low-frequency variations. The low-frequency variation with highest amplitude can be interpreted as rotational modulation with the light curve changing with time. However, the most interesting aspect of this star is a triplet of independent modes in the range 118–129 d−1 (1.4–1.5 mHz), which is far outside the range of typical δ Scuti frequencies. We discuss the possibility that these modes could be solar-like oscillations, oscillations of the roAp type or due to an unseen pulsating compact companion.