A Large Sample of Photometric Rotation Periods for FGK Pleiades Stars - Astrophysics > Solar and Stellar AstrophysicsReport as inadecuate




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Abstract: Using data from the HATNet survey for transiting exoplanets we measurephotometric rotation periods for 368 Pleiades stars with 0.4 Msun < M < 1.3Msun. We detect periodic variability for 74% of the cluster members in thismass range that are within our field-of-view, and 93% of the members with 0.7Msun < M < 1.0 Msun. This increases, by a factor of five, the number ofPleiades members with measured periods. Included in our sample are 14 newlyidentified probable cluster members which have proper motions, photometry, androtation periods consistent with membership. We compare this data to the richsample of spectroscopically determined projected equatorial rotation velocitiesvsini available in the literature for this cluster. For stars with M > 0.85Msun the rotation periods, vsini and radius estimates are consistent with thestars having an isotropic distribution of rotation axes, if a moderatedifferential rotation law is assumed. For stars with M < 0.85 Msun the inferredsini values are systematically larger than 1.0. These observations imply thatthe combination of measured parameters Pvsini-R is too large by \sim 24% forlow-mass stars in this cluster. By comparing our new mass-period relation forthe Pleiades to the slightly older cluster M35, we confirm previous indicationsthat the spin-down stalls at \sim 100 Myr for the slowest rotating stars with0.7 Msun < M < 1.1 Msun a fact which may indicate that the internal transportof angular momentum is inefficient in slowly rotating solar mass stars.



Author: Joel D. Hartman, Gáspár Á Bakos, Géza Kovács, Robert W. Noyes

Source: https://arxiv.org/







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