C. Gourvès, A. Strugarek, C. Moutou, J. Morin, P. Petit, A. Dyrek, S. N. Breton, R. A. García, A. F. Lanza, S. Mathur, A. R. G. Santos

Abstract
With the detection of thousands of exoplanetary systems, previous studies have identified a dearth of close-in exoplanets around fast rotating stars, which can be attributed to strong star-planet tidal and magnetic interactions. These systems evolve rapidly, which makes their detection particularly challenging. To increase the size of the sample of short-period star-planet systems, going beyond detections by transit is necessary. To do so, we applied a method based on phase-curve modulations, which has already proven successful through the discovery of four exoplanets. We identified 88 non-transiting candidates in the Kepler dataset, with orbital periods between 4 hours and 2.3 days. Remarkably, 55 of them would join the class of ultra-short-period planets, a population of particular interest for studying extreme star-planet interactions. To confirm these candidates, we initiated radial velocity follow-up with the SPIRou spectrograph at CFHT. A first allocation of 2.7 hours of Director's time on KIC 12060710 yielded a preliminary confirmation of existence and mass estimate for its substellar companion, which orbits the star in 9 hours. Additional observations have been requested at CFHT to secure this confirmation and to extend the monitoring to two other bright M-dwarfs from our 88 star sample.

Keywords
Methods: data analysis; Planet-star interactions; Planets and satellites: detection; Stars: solar-type; Techniques: radial velocities

SF2A-2025: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics.
K. Baillié A. Siebert

Société Française d’Astronomie et d’Astrophysique (SF2A), Page 461
2025 July

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