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dc.contributor.authorVidotto, Aline
dc.contributor.authorDonati, J.-F.
dc.contributor.authorJardine, Moira Mary
dc.contributor.authorSee, Wyke Chun Victor
dc.contributor.authorPetit, P.
dc.contributor.authorBoisse, I.
dc.contributor.authorBoro Saikia, S.
dc.contributor.authorHébrard, E.
dc.contributor.authorJeffers, Sandra Victoria
dc.contributor.authorMarsden, S. C.
dc.contributor.authorMorin, J.
dc.identifier.citationVidotto , A , Donati , J-F , Jardine , M M , See , W C V , Petit , P , Boisse , I , Boro Saikia , S , Hébrard , E , Jeffers , S V , Marsden , S C & Morin , J 2016 , ' Could a change in magnetic field geometry cause the break in the wind-activity relation? ' , Monthly Notices of the Royal Astronomical Society: Letters , vol. 455 , no. 1 , pp. L52–L56 .
dc.identifier.otherPURE: 241204787
dc.identifier.otherPURE UUID: ff17d601-f95d-4f13-8fed-a0007f5fa186
dc.identifier.otherBibCode: 2016MNRAS.455L..52V
dc.identifier.otherScopus: 85052576493
dc.identifier.otherWOS: 000368005900012
dc.identifier.otherORCID: /0000-0002-1466-5236/work/57821830
dc.descriptionAAV acknowledges support from the Swiss National Science Foundation through an Ambizione Fellowship. SVJ and SBS acknowledge research funding by the Deutsche Forschungsgemeinschaft under grant SFB 963/1, project A16.en
dc.description.abstractWood et al. suggested that mass-loss rate is a function of X-ray flux (dot{M}∝ F_x^{1.34}) for dwarf stars with Fx ≲ Fx,6 ≡ 106 erg cm-2 s-1. However, more active stars do not obey this relation. These authors suggested that the break at Fx,6 could be caused by significant changes in magnetic field topology that would inhibit stellar wind generation. Here, we investigate this hypothesis by analysing the stars in Wood et al. sample that had their surface magnetic fields reconstructed through Zeeman-Doppler Imaging (ZDI). Although the solar-like outliers in the dot{M} - Fx relation have higher fractional toroidal magnetic energy, we do not find evidence of a sharp transition in magnetic topology at Fx,6. To confirm this, further wind measurements and ZDI observations at both sides of the break are required. As active stars can jump between states with highly toroidal to highly poloidal fields, we expect significant scatter in magnetic field topology to exist for stars with Fx ≳ Fx,6. This strengthens the importance of multi-epoch ZDI observations. Finally, we show that there is a correlation between Fx and magnetic energy, which implies that dot{M} - magnetic energy relation has the same qualitative behaviour as the original dot{M} - Fx relation. No break is seen in any of the Fx - magnetic energy relations.
dc.relation.ispartofMonthly Notices of the Royal Astronomical Society: Lettersen
dc.rights© 2015 The Authors, Published by Oxford University Press on behalf of the Royal Astronomical Society. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at
dc.subjectMagnetic fieldsen
dc.subjectStars: activityen
dc.subjectStars: coronaeen
dc.subjectStars: low-massen
dc.subjectStars: windsen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleCould a change in magnetic field geometry cause the break in the wind-activity relation?en
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews.School of Physics and Astronomyen
dc.description.statusPeer revieweden

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