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dc.contributorArmagh Observatory, College Hill, BT61 9DG Armagh, UK ; Université de Toulouse, UPS-Observatoire Midi-Pyrénées, IRAP, Toulouse, France ; CNRS, Institut de Recherche en Astrophysique et Planétologie, 14 av. E. Belin, F-31400 Toulouse, France;
dc.contributorDepartment of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA
dc.contributorUniversité de Bordeaux, Institut de Mathématiques, UMR 5251, 351 cours de la libération, F-33405 Talence cedex, France
dc.contributorUniversité de Toulouse, UPS-Observatoire Midi-Pyrénées, IRAP, Toulouse, France ; CNRS, Institut de Recherche en Astrophysique et Planétologie, 14 av. E. Belin, F-31400 Toulouse, France
dc.contributorDepartment of Physics & Astronomy, Notre Dame University-Louaize, PO Box 72, Zouk Mikaël, Lebanon
dc.contributor.authorHoudebine, E. R.
dc.contributor.authorMullan, D. J.
dc.contributor.authorBercu, B.
dc.contributor.authorPaletou, F.
dc.contributor.authorGebran, M.
dc.date.accessioned2024-02-21T11:02:50Z
dc.date.available2024-02-21T11:02:50Z
dc.date.issued2017-03-01T00:00:00Z
dc.identifier.doi10.3847/1538-4357/aa5cad
dc.identifier.doi10.48550/arXiv.1701.07608
dc.identifier.other2017arXiv170107608H
dc.identifier.otherastro-ph.SR
dc.identifier.other2017ApJ...837...96H
dc.identifier.otherarXiv:1701.07608
dc.identifier.other10.48550/arXiv.1701.07608
dc.identifier.other2017arXiv170107608H
dc.identifier.other10.3847/1538-4357/aa5cad
dc.identifier.other0000-0002-0403-7519
dc.identifier.other-
dc.identifier.other0000-0003-1970-2929
dc.identifier.other0000-0002-8675-4000
dc.identifier.urihttp://hdl.handle.net/20.500.14302/1691
dc.description.abstractWe study the rotation-activity correlations (RACs) in a sample of stars from spectral type dK4 to dM4. We study RACs using chromospheric data and coronal data. We study the Ca II line surface fluxes-P/\sin I RACs. We fit the RACs with linear homoscedastic and heteroscedastic regression models. We find that these RACs differ substantially from one spectral sub-type to another. For dM3 and dM4 stars, we find that the RACs cannot be described by a simple model, but instead that there may exist two distinct RAC behaviors for the low-activity and the high-activity stellar sub-samples, respectively. Although these results are preliminary and will need confirmation, the data suggest that these distinct RACs may be associated with different dynamo regimes. We also study {R}<SUB>{HK</SUB>}<SUP>\prime </SUP> as a function of the Rossby number R <SUB>0</SUB>. We find (I) for dK4 stars, {R}<SUB>{HK</SUB>}<SUP>\prime </SUP> as a function of R <SUB>0</SUB> agrees well with previous results for F-G-K stars and (II) in dK6, dM2, dM3, and dM4 stars, at a given R <SUB>0</SUB>, the values of {R}<SUB>{HK</SUB>}<SUP>\prime </SUP> lie at a factor of 3, 10, 20, and 90, respectively, below the F-G-K RAC. Our results suggest a significant decrease in the efficiency of the dynamo mechanism(s) as regards chromospheric heating before and at dM3, I.e., before and at the transition to complete convection. We also show that the ratio of coronal heating to chromospheric heating L <SUB>X</SUB>/L <SUB>HK</SUB> increases by a factor of 100 between dK4 and dM4 stars. <P />Based on observations available at Observatoire de Haute Provence and the European Southern Observatory databases and on Hipparcos parallax measurements.
dc.publisherThe Astrophysical Journal
dc.titleThe Rotation-Activity Correlations in K and M Dwarfs. II. New Constraints on the Dynamo Mechanisms in Late-K and M Dwarfs Before and At the Transition to Complete Convection
dc.typearticle
dc.source.journalApJ
dc.source.journalApJ...837
dc.source.volume837
refterms.dateFOA2024-02-21T11:02:50Z
dc.identifier.bibcode2017ApJ...837...96H


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