Rotation of Low-mass Stars in Upper Scorpius and ρ Ophiuchus with K2
Abstract
We present an analysis of K2 light curves (LCs) for candidate members of the young Upper Sco (USco) association (~8 Myr) and the neighboring ρ Oph embedded cluster (~1 Myr). We establish ~1300 stars as probable members, ~80% of which are periodic. The phased LCs have a variety of shapes which can be attributed to physical causes ranging from stellar pulsation and stellar rotation to disk-related phenomena. We identify and discuss a number of observed behaviors. The periods are ~0.2–30 days with a peak near 2 days and the rapid period end nearing breakup velocity. M stars in the young USco region rotate systematically faster than GK stars, a pattern also present in K2 data for the older Pleiades and Praesepe systems. At higher masses (types FGK), the well-defined period–color relationship for slowly rotating stars seen in the Pleiades and Praesepe systems is not yet present in USco. Circumstellar disks are present predominantly among the more slowly rotating M stars in USco, with few disks in the subday rotators. However, M dwarfs with disks rotate faster on average than FGK systems with disks. For four of these disked M dwarfs, we provide direct evidence for disk locking based on the K2 LC morphologies. Our preliminary analysis shows a relatively mass-independent spin-up by a factor of ~3.5 between USco and the Pleiades, then mass-dependent spin-down between Pleiades and Praesepe.
Additional Information
© 2018 The American Astronomical Society. Received 2018 February 5; revised 2018 March 8; accepted 2018 March 9; published 2018 April 17. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX09AF08G and by other grants and contracts. This paper includes data collected by the Kepler mission. Funding for the Kepler mission is provided by the NASA Science Mission directorate. This research has made use of the NASA/IPAC Infrared Science Archive (IRSA), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This research has made use of NASA's Astrophysics Data System (ADS) Abstract Service and of the SIMBAD database, operated at CDS, Strasbourg, France. This research has made use of data products from the Two Micron All-Sky Survey (2MASS), which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration and the National Science Foundation. The 2MASS data are served by the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. Facilities: K2 - , 2MASS - , WISE - , IRSA - , Exoplanet Archive.Attached Files
Published - Rebull_2018_AJ_155_196.pdf
Accepted Version - 1803.04440.pdf
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Additional details
- Alternative title
- Rotation of Low-Mass Stars in Upper Scorpius and Rho Ophiuchus with K2
- Eprint ID
- 85890
- Resolver ID
- CaltechAUTHORS:20180417-100047343
- NNX09AF08G
- NASA
- NASA/JPL/Caltech
- NSF
- Created
-
2018-04-17Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC), Astronomy Department