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dc.contributor.authorBarnes, J.R.
dc.contributor.authorJeffers, S.V.
dc.contributor.authorJones, H.R.A.
dc.contributor.authorPavlenko, Ya. V.
dc.contributor.authorJenkins, J. S.
dc.contributor.authorHaswell, C.A.
dc.contributor.authorLohr, M. E.
dc.date.accessioned2016-03-16T10:15:20Z
dc.date.available2016-03-16T10:15:20Z
dc.date.issued2015-10-07
dc.identifier.citationBarnes , J R , Jeffers , S V , Jones , H R A , Pavlenko , Y V , Jenkins , J S , Haswell , C A & Lohr , M E 2015 , ' Starspot distributions on fully convective M dwarfs : implications for radial velocity planet searches ' , The Astrophysical Journal , vol. 812 , no. 1 , 42 . https://doi.org/10.1088/0004-637X/812/1/42
dc.identifier.issn0004-637X
dc.identifier.otherPURE: 9855400
dc.identifier.otherPURE UUID: 56d34f93-63ec-49c4-a218-20ae2de1832c
dc.identifier.otherArXiv: http://arxiv.org/abs/1509.05284v1
dc.identifier.otherScopus: 84946101118
dc.identifier.urihttp://hdl.handle.net/2299/16807
dc.description.abstractSince M4.5 - M9 dwarfs exhibit equatorial rotation velocities of order 10 km/s on average, radial velocity surveys targeting this stellar population will likely need to find methods to effectively remove starspot jitter. We present the first high resolution Doppler images of the M4.5 dwarf, GJ 791.2A, and the M9 dwarf, LP 944-20. The time series spectra of both objects reveal numerous line profile distortions over the rotation period of each star which we interpret as starspots. The transient distortions are modelled with spot/photosphere contrast ratios that correspond to model atmosphere temperature differences of Tphot-Tspot = 200 and 300 K. GJ 791.2A is a fully convective star with vsini = 35.1 km/s. Although we find more starspot structure at high latitudes, we reconstruct spots at a range of phases and latitudes with a mean spot filling of ~3%. LP 944-20 is one of the brightest known late-M dwarfs, with spectral type M9V and vsini = 30.8 km/s. Its spectral time series exhibits two dominant transient line distortions that are reconstructed as high latitude spots, while a mean spot filling factor of only 1.5% is found. The occurrence of low-contrast spots at predominantly high latitudes, which we see in both targets here, is in general likely to be responsible for the low amplitude photometric variability seen in late-M dwarfs. For GJ 791.2A, the radial velocities induced by the starspot features yield an rms velocity variability of 138 m/s, which can be reduced by a factor of 1.9 using our reconstructed surface brightness distributions.en
dc.format.extent14
dc.language.isoeng
dc.relation.ispartofThe Astrophysical Journal
dc.rights/dk/atira/pure/core/openaccesspermission/open
dc.subjectastro-ph.SR
dc.titleStarspot distributions on fully convective M dwarfs : implications for radial velocity planet searchesen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionCentre for Astrophysics Research
dc.description.statusPeer reviewed
dc.relation.schoolSchool of Physics, Astronomy and Mathematics
dc.description.versiontypeFinal Accepted Version
dcterms.dateAccepted2015-08-26
rioxxterms.versionAM
rioxxterms.versionofrecordhttps://doi.org/10.1088/0004-637X/812/1/42
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.rights.accesstypeopenAccess


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