Surface rotation and photometric magnetic activity for 55,000+ solar-like stars observed by Kepler
Abstract
Dark magnetic spots or bright faculae co-rotating with the stellar surface lead to quasi-periodic brightness variations, which enclose relevant information on stellar rotation and magnetic activity. In this work, we analyzed Kepler long-cadence data of 159,442 main-sequence and subgiant FGKM stars. Rotation-period candidates are obtained from the light curves by three methods: wavelet analysis, autocorrelation function, and their composite spectrum. The final rotation periods (Prot) are selected via a machine learning algorithm (ROOSTER), automatic selection, and complementary visual inspection. We successfully recover Prot and the photometric magnetic activity proxy (Sph) for 55,232 stars, which corresponds to an increase in detections of more than 60% in comparison with McQuillan et al. (2014). In particular, the upper edge of the Prot distribution is found to be located at longer periods than found previously, which has been theoretically predicted. The Prot distribution is confirmed to be bimodal, showing a slow- and a fast-rotating branch separated by a period "gap". While Prot generally decreases with increasing effective temperature, the Sph behavior is more complex: M dwarfs typically exhibit large Sph values; Sph slightly decreases for late K dwarfs; then the upper edge of the Sph distribution slightly shifts towards large values, while the lower edge moves swiftly towards smaller Sph; finally F dwarfs typically have small Sph values. For main-sequence GKM stars, magnetic activity and rotation are related, with fast rotators being generally more active than slow rotators. Because of the bimodal Prot distribution, there are two regimes in the activity-rotation diagram, with both slow- and fast-rotating branches being rotation dependent. While stars in the fast-rotating branch tend to have large Sph values, we do not find other significant differences in the Sph behavior between the two branches. The availability of these catalogs for such a large number of stars are important to shed light on rotation and magnetic evolution of solar-like stars.
- Publication:
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The 21st Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun
- Pub Date:
- December 2022
- DOI:
- Bibcode:
- 2022csss.confE..96S
- Keywords:
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- stars: low-mass;
- stars: rotation;
- stars: activity;
- starspots;
- Sun: activity;
- techniques: photometric;
- methods: data analysis;
- Zenodo community cs21