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Calculations of periodicity from Halpha profiles of Proxima Centauri

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contributor authorCollins, John
contributor authorJones, Hugh
contributor authorBarnes, John
date accessioned2018-06-11T16:41:55Z
date available2018-06-11T16:41:55Z
date issued2017-06-07
identifier citationCollins , J , Jones , H & Barnes , J 2017 , ' Calculations of periodicity from Halpha profiles of Proxima Centauri ' Astronomy & Astrophysics , vol 602 . DOI: 10.1051/0004-6361/201628827en
identifier issn0004-6361
identifier otherPURE: 10455438
identifier otherPURE UUID: 9aa28599-9b2d-46d6-a60d-baa2067652ce
identifier otherScopus: 85018180133
identifier urihttp://hdl.handle.net/2299/20176
identifier urihttp://arxiv.org/abs/1608.07834en
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.en
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
format extent8en
language isoeng
relation ispartofAstronomy & Astrophysicsen
rightsen
titleCalculations of periodicity from Halpha profiles of Proxima Centaurien
typeArticleen
contributor institutionSchool of Physics, Astronomy and Mathematicsen
contributor institutionCentre for Astrophysics Researchen
identifier doihttps://doi.org/10.1051/0004-6361/201628827
description versionpublishersversionen
description statusPeer revieweden


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