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Untangling the Galaxy. IV. Empirical Constraints on Angular Momentum Evolution and Gyrochronology for Young Stars in the Field

Kounkel, Marina and Stassun, Keivan G. and Bouma, Luke G. and Covey, Kevin and Hillenbrand, Lynne A. and Curtis, Jason Lee (2022) Untangling the Galaxy. IV. Empirical Constraints on Angular Momentum Evolution and Gyrochronology for Young Stars in the Field. Astronomical Journal, 164 (4). Art. No. 137. ISSN 0004-6256. doi:10.3847/1538-3881/ac866d.

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We present a catalog of ∼100,000 periodic variable stars in Transiting Exoplanet Survey Satellite (TESS) full-frame image data among members of widely distributed moving groups identified with Gaia in the previous papers in the series. By combining the periods from our catalog attributable to rotation with previously derived rotation periods for benchmark open clusters, we develop an empirical gyrochronology relation of angular momentum evolution that is valid for stars with ages 10–1000 Myr. Excluding stars rotating faster than 2 days, which we find are predominantly binaries, we achieve a typical age precision of ≈0.2–0.3 dex and improving at older ages. Importantly, these empirical relations apply to not only FGK-type stars but also M-type stars, due to the angular momentum distribution being much smoother, simpler, continuous, and monotonic as compared to the rotation period distribution. As a result, we are also able to begin tracing in fine detail the nature of angular momentum loss in low-mass stars as functions of mass and age. We characterize the stellar variability amplitudes of the cool stars as functions of mass and age, which may correlate with the starspot covering fractions. We also identify pulsating variables among the hotter stars in the catalog, including δ Scuti, γ Dor, and slowly pulsating B-type variables. These data represent an important step forward in being able to estimate precise ages of FGK- and M-type stars in the field, starting as early as the pre-main-sequence phase of evolution.

Item Type:Article
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URLURL TypeDescription ItemDiscussion Paper
Kounkel, Marina0000-0002-5365-1267
Stassun, Keivan G.0000-0002-3481-9052
Bouma, Luke G.0000-0002-0514-5538
Covey, Kevin0000-0001-6914-7797
Curtis, Jason Lee0000-0002-2792-134X
Additional Information:We acknowledge funding from Vanderbilt initiative in data intensive astrophysics (VIDA). This work has made use of data from the European Space Agency (ESA) mission Gaia (, processed by the Gaia Data Processing and Analysis Consortium (DPAC, forthe DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
Funding AgencyGrant Number
Vanderbilt Initiative in Data-Intensive Astrophysics (VIDA)UNSPECIFIED
Gaia Multilateral AgreementUNSPECIFIED
Issue or Number:4
Record Number:CaltechAUTHORS:20220920-893152900
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117102
Deposited By: Melissa Ray
Deposited On:25 Sep 2022 13:53
Last Modified:25 Sep 2022 13:53

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