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dc.contributor.authorNewton, Elisabeth R
dc.contributor.authorIrwin, Jonathan
dc.contributor.authorCharbonneau, David
dc.contributor.authorBerta-Thompson, Zachory K.
dc.contributor.authorDittmann, Jason Adam
dc.contributor.authorWest, Andrew A.
dc.date.accessioned2017-01-10T23:04:38Z
dc.date.issued2016
dc.identifier.citationNewton, Elisabeth R., Jonathan Irwin, David Charbonneau, Zachory K. Berta-Thompson, Jason A. Dittmann, and Andrew A. West. 2016. The Rotation and Galactic Kinematics of Mid M Dwarfs in the Solar Neighborhood. The Astrophysical Journal 821, no. 2: 93. doi:10.3847/0004-637x/821/2/93.en_US
dc.identifier.issn1538-4357en_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:29914200
dc.description.abstractRotation is a directly observable stellar property, and it drives magnetic field generation and activity through a magnetic dynamo. Main-sequence stars with masses below approximately 0.35 ${M}_{\odot }$ (mid-to-late M dwarfs) are fully convective, and are expected to have a different type of dynamo mechanism than solar-type stars. Measurements of their rotation rates provide insight into these mechanisms, but few rotation periods are available for these stars at field ages. Using photometry from the MEarth Project, we measure rotation periods for 387 nearby, mid-to-late M dwarfs in the northern hemisphere, finding periods from 0.1 to 140 days. The typical rotator has stable, sinusoidal photometric modulations at a semi-amplitude of 0.5%–1%. We find no period–amplitude relation for stars below 0.25 ${M}_{\odot }$ and an anticorrelation between period and amplitude for higher-mass M dwarfs. We highlight the existence of older, slowly rotating stars without Hα emission that nevertheless have strong photometric variability. We use parallaxes, proper motions, radial velocities, photometry, and near-infrared metallicity estimates to further characterize the population of rotators. The Galactic kinematics of our sample is consistent with the local population of G and K dwarfs, and rotators have metallicities characteristic of the solar neighborhood. We use the W space velocities and established age–velocity relations to estimate that stars with P < 10 days have ages of on average <2 Gyr, and that those with P > 70 days have ages of about 5 Gyr. The period distribution is dependent on mass: as the mass decreases, the slowest rotators at a given mass have longer periods, and the fastest rotators have shorter periods. We find a lack of stars with intermediate rotation periods, and the gap between the fast and slow rotators is larger for lower masses. Our data are consistent with a scenario in which these stars maintain rapid rotation for several gigayears, then spin down quickly, reaching periods of around 100 days by a typical age of 5 Gyr.en_US
dc.description.sponsorshipAstronomyen_US
dc.language.isoen_USen_US
dc.publisherAmerican Astronomical Societyen_US
dc.relation.isversionofdoi:10.3847/0004-637x/821/2/93en_US
dc.relation.hasversionhttps://arxiv.org/pdf/1511.00957.pdfen_US
dash.licenseOAP
dc.subjectstars: rotationen_US
dc.subjectstars: low-massen_US
dc.subjectstars: kinematics and dynamicsen_US
dc.subjectstars: starspotsen_US
dc.titleThe Rotation and Galactic Kinematics of Mid M Dwarfs in the Solar Neighborhooden_US
dc.typeJournal Articleen_US
dc.description.versionAccepted Manuscripten_US
dc.relation.journalThe Astrophysical Journalen_US
dash.depositing.authorCharbonneau, David
dc.date.available2017-01-10T23:04:38Z
dc.identifier.doi10.3847/0004-637x/821/2/93*
dash.contributor.affiliatedNewton, Elisabeth R
dash.contributor.affiliatedIrwin, Jonathan
dash.contributor.affiliatedDittmann, Jason Adam
dash.contributor.affiliatedCharbonneau, David
dc.identifier.orcid0000-0003-4150-841X


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