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dc.contributor.authorBarnes, J R
dc.contributor.authorCollier Cameron, A
dc.contributor.authorUnruh, Y C
dc.contributor.authorDonati, J F
dc.contributor.authorHussain, G A J
dc.identifier.citationBarnes , J R , Collier Cameron , A , Unruh , Y C , Donati , J F & Hussain , G A J 1998 , ' Latitude distributions and lifetimes of star-spots on G dwarfs in the alpha Persei cluster ' , Monthly Notices of the Royal Astronomical Society , vol. 299 , no. 3 , pp. 904-920 .
dc.identifier.otherPURE: 493097
dc.identifier.otherPURE UUID: 4ce46b95-48a8-4841-86f3-31d6fcdf436c
dc.identifier.otherWOS: 000076227900031
dc.identifier.otherScopus: 0000748184
dc.description.abstractWe present a set of maximum-entropy reconstructions of the star-spot distributions on two rapidly rotating G dwarfs in the alpha Persei cluster, from spectra taken at the William Herschel Telescope on three nights in 1996 October and November. Since these stars are too faint for conventional Doppler imaging, which makes use of only one or a few lines, we take the large number of photospheric metal lines available in an echelle spectrum, and deconvolve them into a single, high signal-to-noise ratio profile. We show that this technique results in a typical multiplex gain of 22.5 in signal-to-noise ratio for a given spectrum, the equivalent of using a single line obtained on a 63-m telescope. The image reconstructions demonstrate that both these stars have cool high-latitude regions or polar crowns, and low-latitude features, in contradiction to the suggestion that only high-latitude spots should be present. Cross-correlation between image reconstructions of He 699, 31 days apart, reveals a lack of correlation between detailed small-scale structures. This places an upper limit for the lifetime of the observed features at less than one month. The H alpha profiles are also found to exhibit absorption features indicating the presence of prominence clouds, at or below the corotation radius.en
dc.relation.ispartofMonthly Notices of the Royal Astronomical Society
dc.subjectline, profiles
dc.subjectmethods, data analysis
dc.subjecttechniques, miscellaneous
dc.subjectstars, activity
dc.subjectstars, atmospheres
dc.subjectstars, late-type
dc.titleLatitude distributions and lifetimes of star-spots on G dwarfs in the alpha Persei clusteren
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.description.statusPeer reviewed
rioxxterms.typeJournal Article/Review

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