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dc.contributor.authorCollins, John
dc.contributor.authorJones, Hugh
dc.contributor.authorBarnes, John
dc.date.accessioned2018-06-11T16:41:55Z
dc.date.available2018-06-11T16:41:55Z
dc.date.issued2017-06-07
dc.identifier.citationCollins , J , Jones , H & Barnes , J 2017 , ' Calculations of periodicity from Halpha profiles of Proxima Centauri ' Astronomy & Astrophysics , vol. 602 . https://doi.org/10.1051/0004-6361/201628827
dc.identifier.issn0004-6361
dc.identifier.otherPURE: 10455438
dc.identifier.otherPURE UUID: 9aa28599-9b2d-46d6-a60d-baa2067652ce
dc.identifier.otherScopus: 85018180133
dc.identifier.urihttp://hdl.handle.net/2299/20176
dc.description© ESO, 2017 Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
dc.description.abstractWe investigate retrieval of the stellar rotation signal for Proxima Centauri. We make use of high-resolution spectra taken with UVES and HARPS of Proxima Centauri over a 13-yr period as well as photometric observations of Proxima Centauri from ASAS and HST. We measure the Hα equivalent width and Hα index, skewness and kurtosis and introduce a method that investigates the symmetry of the line, the peak ratio, which appears to return better results than the other measurements. Our investigations return a most significant period of 82.6 ± 0.1 days, confirming earlier photometric results and ruling out a more recent result of 116.6 days which we conclude to be an alias induced by the specific HARPS observation times. We conclude that whilst spectroscopic Hα measurements can be used for period recovery, in the case of Proxima Centauri the available photometric measurements are more reliable. We make 2D models of Proxima Centauri to generate simulated Hα, finding that reasonable distributions of plage and chromospheric features are able to reproduce the equivalent width variations in observed data and recover the rotation period, including after the addition of simulated noise and flares. However the 2D models used fail to generate the observed variety of line shapes measured by the peak ratio. We conclude that only 3D models which incorporate vertical motions in the chromosphere can achieve this.en
dc.format.extent8
dc.language.isoeng
dc.relation.ispartofAstronomy & Astrophysics
dc.rights/dk/atira/pure/core/openaccesspermission/open
dc.titleCalculations of periodicity from Halpha profiles of Proxima Centaurien
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionCentre for Astrophysics Research
dc.description.statusPeer reviewed
dc.identifier.urlhttp://arxiv.org/abs/1608.07834
dc.relation.schoolSchool of Physics, Astronomy and Mathematics
dc.description.versiontypeFinal Published version
dcterms.dateAccepted2017-02-02
rioxxterms.versionAM
rioxxterms.versionVoR
rioxxterms.versionofrecordhttps://doi.org/10.1051/0004-6361/201628827
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.rights.accesstypeopenAccess


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