Rotation in the Pleiades with K2. III. Speculations on origins and evolution

Stauffer, John and Rebull, Luisa and Bouvier, Jerome and Hillenbrand, Lynne A. and Collier-Cameron, Andrew and Pinsonneault, Marc and Aigrain, Suzanne and Barrado, David and Bouy, Herve and Ciardi, David and Cody, Ann Marie and David, Trevor and Micela, Giusi and Soderblom, David and Somers, Garrett and Stassun, Keivan G. and Valenti, Jeff and Vrba, Frederick J. (2016) Rotation in the Pleiades with K2. III. Speculations on origins and evolution. The Astronomical Journal, 152 (5 (Article 115)). pp. 1-22. ISSN 0004-6256

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Abstract

We use high-quality K2 light curves for hundreds of stars in the Pleiades to better understand the angular momentum evolution and magnetic dynamos of young low-mass stars. The K2 light curves provide not only rotational periods but also detailed information from the shape of the phased light curve that was not available in previous studies. A slowly rotating sequence begins at ∼ 1.1 (spectral type F5) and ends at ∼ 3.7 (spectral type K8), with periods rising from ∼2 to ∼11 days in that interval. A total of 52% of the Pleiades members in that color interval have periods within 30% of a curve defining the slow sequence; the slowly rotating fraction decreases significantly redward of = 2.6. Nearly all of the slow-sequence stars show light curves that evolve significantly on timescales less than the K2 campaign duration. The majority of the FGK Pleiades members identified as photometric binaries are relatively rapidly rotating, perhaps because binarity inhibits star-disk angular momentum loss mechanisms during pre-main-sequence evolution. The fully convective late M dwarf Pleiades members (5.0 < < 6.0) nearly always show stable light curves, with little spot evolution or evidence of differential rotation. During pre-main-sequence evolution from ∼3 Myr (NGC 2264 age) to ∼125 Myr (Pleiades age), stars of 0.3 shed about half of their angular momentum, with the fractional change in period between 3 and 125 Myr being nearly independent of mass for fully convective stars. Our data also suggest that very low mass binaries form with rotation periods more similar to each other and faster than would be true if drawn at random from the parent population of single stars


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published version made available in accordance with the copyright policy of the publisher.
Faculty / Department / School: No Faculty
Date Deposited: 26 May 2017 06:07
Last Modified: 29 May 2017 06:02
Uncontrolled Keywords: open clusters and associations: individual (Pleiades); stars: rotation
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020104 Galactic Astronomy
Identification Number or DOI: 10.3847/0004-6256/152/5/115
URI: http://eprints.usq.edu.au/id/eprint/32435

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