A Knee-Point in the Rotation-Activity Scaling of Late-type Stars with a Connection to Dynamo Transitions

dc.contributorAalto-yliopistofi
dc.contributorAalto Universityen
dc.contributor.authorLehtinen, Jyri J.en_US
dc.contributor.authorKäpylä, Maarit J.en_US
dc.contributor.authorOlspert, Nigulen_US
dc.contributor.authorSpada, Federicoen_US
dc.contributor.departmentDepartment of Computer Scienceen
dc.contributor.groupauthorProfessorship Korpi-Lagg Maariten
dc.contributor.groupauthorCentre of Excellence Research on Solar Long-Term Variability and Effects, ReSoLVEen
dc.contributor.organizationMax Planck Institute for Solar System Researchen_US
dc.date.accessioned2021-04-20T06:47:08Z
dc.date.available2021-04-20T06:47:08Z
dc.date.issued2021-04-01en_US
dc.description| openaire: EC/H2020/824135/EU//SOLARNET | openaire: EC/H2020/818665/EU//UniSDyn
dc.description.abstractThe magnetic activity of late-type stars is correlated with their rotation rates. Up to a certain limit, stars with smaller Rossby numbers, defined as the rotation period divided by the convective turnover time, have higher activity. A more detailed look at this rotation-activity relation reveals that, rather than being a simple power law relation, the activity scaling has a shallower slope for the low-Rossby stars than for the high-Rossby ones. We find that, for the chromospheric CaII H&K activity, this scaling relation is well modelled by a broken two-piece power law. Furthermore, the knee-point of the relation coincides with the axisymmetry to non-axisymmetry transition seen in both the spot activity and surface magnetic field configuration of active stars. We interpret this knee-point as a dynamo transition between dominating axi- and non-axisymmetric dynamo regimes with a different dependence on rotation and discuss this hypothesis in the light of current numerical dynamo models.en
dc.description.versionPeer revieweden
dc.format.extent8
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationLehtinen, J J, Käpylä, M J, Olspert, N & Spada, F 2021, ' A Knee-Point in the Rotation-Activity Scaling of Late-type Stars with a Connection to Dynamo Transitions ', The Astrophysical Journal, vol. 910, no. 2, 110 . https://doi.org/10.3847/1538-4357/abe621en
dc.identifier.doi10.3847/1538-4357/abe621en_US
dc.identifier.issn0004-637X
dc.identifier.otherPURE UUID: 49fd8e07-370c-4c83-b922-1c8625310417en_US
dc.identifier.otherPURE ITEMURL: https://research.aalto.fi/en/publications/49fd8e07-370c-4c83-b922-1c8625310417en_US
dc.identifier.otherPURE LINK: http://www.scopus.com/inward/record.url?scp=85103677481&partnerID=8YFLogxKen_US
dc.identifier.otherPURE LINK: https://arxiv.org/abs/2007.00040en_US
dc.identifier.otherPURE LINK: http://adsabs.harvard.edu/abs/2020arXiv200700040Len_US
dc.identifier.otherPURE FILEURL: https://research.aalto.fi/files/53596410/2007.00040en_US
dc.identifier.urihttps://aaltodoc.aalto.fi/handle/123456789/106867
dc.identifier.urnURN:NBN:fi:aalto-202104206161
dc.language.isoenen
dc.publisherIOP Publishing Ltd.
dc.relationinfo:eu-repo/grantAgreement/EC/H2020/818665/EU//UniSDynen_US
dc.relation.ispartofseriesAstrophysical Journalen
dc.relation.ispartofseriesVolume 910, issue 2en
dc.rightsopenAccessen
dc.subject.keywordAstrophysics - Solar and Stellar Astrophysicsen_US
dc.titleA Knee-Point in the Rotation-Activity Scaling of Late-type Stars with a Connection to Dynamo Transitionsen
dc.typeA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessäfi

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