dc.contributor.author | See, V | |
dc.contributor.author | Matt, SP | |
dc.contributor.author | Finley, AJ | |
dc.contributor.author | Folsom, CP | |
dc.contributor.author | Saikia, SB | |
dc.contributor.author | Donati, J-F | |
dc.contributor.author | Fares, R | |
dc.contributor.author | Hébrard, ÉM | |
dc.contributor.author | Jardine, MM | |
dc.contributor.author | Jeffers, SV | |
dc.contributor.author | Marsden, SC | |
dc.contributor.author | Mengel, MW | |
dc.contributor.author | Morin, J | |
dc.contributor.author | Petit, P | |
dc.contributor.author | Vidotto, AA | |
dc.contributor.author | Waite, IA | |
dc.date.accessioned | 2019-10-17T12:10:03Z | |
dc.date.issued | 2019-11-27 | |
dc.description.abstract | Main sequence low-mass stars are known to spin-down as a consequence of their magnetised stellar winds. However, estimating the precise rate of this spin-down is an open problem. The mass-loss rate, angular momentum-loss rate and the magnetic field properties of low-mass stars are fundamentally linked making this a challenging task. Of particular interest is the stellar magnetic field geometry. In this work, we consider whether non-dipolar field modes contribute significantly to the spin-down of low-mass stars. We do this using a sample of stars that have all been previously mapped with Zeeman-Doppler imaging. For a given star, as long as its mass-loss rate is below some critical mass-loss rate, only the dipolar fields contribute to its spin-down torque. However, if it has a larger mass-loss rate, higher order modes need to be considered. For each star, we calculate this critical mass-loss rate, which is a simple function of the field geometry. Additionally, we use two methods of estimating mass-loss rates for our sample of stars. In the majority of cases, we find that the estimated mass-loss rates do not exceed the critical mass-loss rate and hence, the dipolar magnetic field alone is sufficient to determine the spin-down torque. However, we find some evidence that, at large Rossby numbers, non-dipolar modes may start to contribute. | en_GB |
dc.description.sponsorship | European Union Horizon 2020 | en_GB |
dc.description.sponsorship | Austrian Research Promotion Agency (FFG) | en_GB |
dc.description.sponsorship | FWF NFN | en_GB |
dc.description.sponsorship | German Science Foundation (DFG) Research Unit | en_GB |
dc.description.sponsorship | Irish Research Council | en_GB |
dc.identifier.citation | Vol. 886 (2), article 120 | en_GB |
dc.identifier.doi | 10.3847/1538-4357/ab46b2 | |
dc.identifier.grantnumber | 682393 | en_GB |
dc.identifier.grantnumber | ASAP11 | en_GB |
dc.identifier.grantnumber | S11601-N16 | en_GB |
dc.identifier.grantnumber | S11604-N16 | en_GB |
dc.identifier.grantnumber | JE 701/3-1 | en_GB |
dc.identifier.grantnumber | RE 1664/18 | en_GB |
dc.identifier.uri | http://hdl.handle.net/10871/39256 | |
dc.language.iso | en | en_GB |
dc.publisher | American Astronomical Society / IOP Publishing | en_GB |
dc.rights | © 2019. The American Astronomical Society. All rights reserved. | |
dc.subject | magnetohydrodynamics (MHD) | en_GB |
dc.subject | stars: low-mass | en_GB |
dc.subject | stars: stellar winds, outflows | en_GB |
dc.subject | stars: magnetic field | en_GB |
dc.subject | stars: rotation, evolution | en_GB |
dc.title | Do non-dipolar magnetic fields contribute to spin-down torques? | en_GB |
dc.type | Article | en_GB |
dc.date.available | 2019-10-17T12:10:03Z | |
dc.description | This is the final version. Available from the American Astronomical Society via the DOI in this record | en_GB |
dc.identifier.eissn | 1538-4357 | |
dc.identifier.journal | Astrophysical Journal | en_GB |
dc.rights.uri | http://www.rioxx.net/licenses/all-rights-reserved | en_GB |
dcterms.dateAccepted | 2019-09-20 | |
exeter.funder | ::European Commission | en_GB |
rioxxterms.version | VoR | en_GB |
rioxxterms.licenseref.startdate | 2019-09-20 | |
rioxxterms.type | Journal Article/Review | en_GB |
refterms.dateFCD | 2019-10-17T12:04:49Z | |
refterms.versionFCD | AM | |
refterms.dateFOA | 2020-02-14T12:04:36Z | |
refterms.panel | B | en_GB |