Possible planets around A stars
Abstract
Kepler photometry of A stars shows that a considerable fraction (about 19 per cent) have a peculiar feature in the periodogram. This feature consists of a broad peak, thought to be due to differential rotation in a spotted star, and a sharp peak at slightly higher frequency. The pattern clearly involves some widespread stellar property and the sharp peak implies a strictly coherent periodicity. We investigate the possibility that the periodicity is due to rotation, pulsation or an orbital effect. We argue that neither rotation nor pulsation can provide a suitable, testable, explanation. We suggest that the sharp feature could be due to a planet in synchronous orbit around the rapidly rotating, spotted A star, not necessarily in transit. Spectroscopic observations of sufficient precision are required to falsify this hypothesis.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2014
- DOI:
- 10.1093/mnras/stu822
- Bibcode:
- 2014MNRAS.441.3543B
- Keywords:
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- stars: activity;
- stars: oscillations;
- planetary systems;
- stars: rotation