Activity and differential rotation of the early M dwarf Kepler-45 from transit mapping

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dc.contributor.authorZaleski S.M.
dc.contributor.authorValio A.
dc.contributor.authorCarter B.D.
dc.contributor.authorMarsden S.C.
dc.date.accessioned2024-03-12T23:48:35Z
dc.date.available2024-03-12T23:48:35Z
dc.date.issued2020
dc.description.abstract© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.Little is known of the activity and differential rotation of low luminosity, early M dwarfs from direct observation. We present the first stellar activity analysis of star-spots and faculae for the hot Jupiter hosting M1V dwarf Kepler-45 from Kepler transit light curves. We find star-spot and facula temperatures contrasting a few hundred degrees with the quiet photosphere, hence similar to other early M dwarfs having a convective envelope surrounding a radiative core. Star-spots are prominent close to the centre of the stellar disc, with faculae prominent towards the limbs, similar to what is observed for the Sun. Star-spot and facula mean sizes are about 40 and 45 × 103 km, respectively, and thus faculae occupy a 10 per cent larger surface area than the star-spots. A short-term activity cycle of about 295 d is observed that is reminiscent of those seen for other cool dwarfs. Adopting a solar-type differential rotation profile (faster equatorial rotation than polar rotation), our star-spot and facula temporal mapping indicates a rotation period of 15.520 ± 0.025 d at the transit latitude of -33.2°. From the mean stellar rotation of 15.762 d, we estimate a rotational shear of 0.031 ± 0.004 rad d-1, or a relative differential rotation of 7.8 ± 0.9 per cent. Kepler-45's surface rotational shear is thus consistent with observations and theoretical modelling of other early M dwarfs that indicate a shear of less than 0.045 rad d-1 and no less than 0.03 rad d-1 for stars with similar stellar rotation periods.
dc.description.firstpage5141
dc.description.issuenumber4
dc.description.lastpage5151
dc.description.volume492
dc.identifier.doi10.1093/mnras/staa103
dc.identifier.issn1365-2966
dc.identifier.urihttps://dspace.mackenzie.br/handle/10899/35014
dc.relation.ispartofMonthly Notices of the Royal Astronomical Society
dc.rightsAcesso Aberto
dc.subject.otherlanguagestars: activity
dc.subject.otherlanguagestars: solar-type
dc.subject.otherlanguagestarspots
dc.titleActivity and differential rotation of the early M dwarf Kepler-45 from transit mapping
dc.typeArtigo
local.scopus.citations10
local.scopus.eid2-s2.0-85100307932
local.scopus.subjectDifferential rotation
local.scopus.subjectDirect observations
local.scopus.subjectRotation period
local.scopus.subjectRotational shear
local.scopus.subjectStar spots
local.scopus.subjectStar: activity
local.scopus.subjectStars: solar types
local.scopus.subjectStarspots
local.scopus.subjectStellar rotation
local.scopus.subjectStellars
local.scopus.updated2024-05-01
local.scopus.urlhttps://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85100307932&origin=inward
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