Monitoring the large-scale magnetic field of AD Leo with SPIRou, ESPaDOnS, and Narval: towards a magnetic polarity reversal?

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dc.creatorStefano Bellotti
dc.creatorJulien Morin
dc.creatorLucien Lehmann
dc.creatorColin Peter Folsom
dc.creatorGaitee Hussain
dc.creatorPascal Petit
dc.creatorJean-Francois Donati
dc.creatorAlexis Lavail
dc.creatorAndres Carmona
dc.creatorEder Martioli
dc.creatorBonnie Zaire
dc.creatorEvelyne Alecian
dc.creatorClaire Moutou
dc.creatorPascal Fouqué
dc.creatorSilvia Helena Paixão Alencar
dc.creatorEtienne Artigau
dc.creatorIsabelle Boisse
dc.creatorFrancois Bouchy
dc.creatorCharles Cadieux
dc.creatorRyan Cloutier
dc.creatorNeil James Cook
dc.creatorXavier Delfosse
dc.creatorRene Doyon
dc.creatorGuillaume Hébrard
dc.creatorOleg Kochukhov
dc.creatorGregg Wade
dc.date.accessioned2025-02-10T19:41:45Z
dc.date.accessioned2025-09-09T01:01:52Z
dc.date.available2025-02-10T19:41:45Z
dc.date.issued2023-08-09
dc.format.mimetypepdf
dc.identifier.doihttps://doi.org/10.1051/0004-6361/202346845
dc.identifier.issn0004-6361
dc.identifier.urihttps://hdl.handle.net/1843/79830
dc.languageeng
dc.publisherUniversidade Federal de Minas Gerais
dc.relation.ispartofAstronomy & Astrophysics
dc.rightsAcesso Aberto
dc.subjectCampos magnéticos
dc.subjectEstrelas
dc.subjectEstrelas - Campos magnéticos
dc.subject.otherstars: individual
dc.subject.otherstars: activity
dc.subject.otherAD Leo
dc.subject.otherstars: magnetic field
dc.subject.othertechniques: polarimetric
dc.titleMonitoring the large-scale magnetic field of AD Leo with SPIRou, ESPaDOnS, and Narval: towards a magnetic polarity reversal?
dc.typeArtigo de periódico
local.citation.epage56
local.citation.spage01
local.citation.volume676
local.description.resumoContext. One clear manifestation of dynamo action on the Sun is the 22-yr magnetic cycle, exhibiting a polarity reversal and a periodic conversion between poloidal and toroidal fields. For M dwarfs, several authors claim evidence of activity cycles from photometry and analyses of spectroscopic indices, but no clear polarity reversal has been identified from spectropolarimetric observations. These stars are excellent laboratories to investigate dynamo-powered magnetic fields under different stellar interior conditions, that is partly or fully convective. Aims. Our aim is to monitor the evolution of the large-scale field of AD Leo, which has shown hints of a secular evolution from past dedicated spectropolarimetric campaigns. This is of central interest to inform distinct dynamo theories, contextualise the evolution of the solar magnetic field, and explain the variety of magnetic field geometries observed in the past. Methods. We analysed near-infrared spectropolarimetric observations of the active M dwarf AD Leo taken with SPIRou between 2019 and 2020 and archival optical data collected with ESPaDOnS and Narval between 2006 and 2019. We searched for long-term variability in the longitudinal field, the width of unpolarised Stokes profiles, the unsigned magnetic flux derived from Zeeman broadening, and the geometry of the large-scale magnetic field using both Zeeman-Doppler imaging and principal component analysis. Results. We found evidence of a long-term evolution of the magnetic field, featuring a decrease in axisymmetry (from 99% to 60%). This is accompanied by a weakening of the longitudinal field (−300 to −50 G) and a correlated increase in the unsigned magnetic flux (2.8–3.6 kG). Likewise, the width of the mean profile computed with selected near-infrared lines manifests a long-term evolution corresponding to field strength changes over the full time series, but does not exhibit modulation with the stellar rotation of AD Leo in individual epochs. Conclusions. The large-scale magnetic field of AD Leo manifested first hints of a polarity reversal in late 2020 in the form of a substantially increased dipole obliquity, while the topology remained predominantly poloidal and dipolar for 14 yr. This suggests that low-mass M dwarfs with a dipole-dominated magnetic field can undergo magnetic cycles.
local.identifier.orcidhttps://orcid.org/0000-0002-2558-6920
local.identifier.orcidhttps://orcid.org/0000-0002-4996-6901
local.identifier.orcidhttps://orcid.org/0000-0001-7108-9119
local.identifier.orcidhttps://orcid.org/0000-0002-9023-7890
local.identifier.orcidhttps://orcid.org/0000-0003-3547-3783
local.identifier.orcidhttps://orcid.org/0000-0001-7624-9222
local.identifier.orcidhttps://orcid.org/0000-0001-5541-2887
local.identifier.orcidhttps://orcid.org/0000-0001-8477-5265
local.identifier.orcidhttps://orcid.org/0000-0003-2471-1299
local.identifier.orcidhttps://orcid.org/0000-0002-5084-168X
local.identifier.orcidhttps://orcid.org/0000-0002-9328-9530
local.identifier.orcidhttps://orcid.org/0000-0001-5260-7179
local.identifier.orcidhttps://orcid.org/0000-0002-2842-3924
local.identifier.orcidhttps://orcid.org/0000-0002-1436-7351
local.identifier.orcidhttps://orcid.org/0000-0002-5171-8376
local.identifier.orcidhttps://orcid.org/0000-0003-3506-5667
local.identifier.orcidhttps://orcid.org/0000-0002-7613-393X
local.identifier.orcidhttps://orcid.org/0000-0001-9291-5555
local.identifier.orcidhttps://orcid.org/0000-0001-5383-9393
local.identifier.orcidhttps://orcid.org/0000-0003-4166-4121
local.identifier.orcidhttps://orcid.org/0000-0001-5099-7978
local.identifier.orcidhttps://orcid.org/0000-0001-5485-4675
local.identifier.orcidhttps://orcid.org/0000-0001-5450-7067
local.identifier.orcidhttps://orcid.org/0000-0003-3061-4591
local.identifier.orcidhttps://orcid.org/0000-0002-1854-0131
local.publisher.countryBrasil
local.publisher.departmentICX - DEPARTAMENTO DE FÍSICA
local.publisher.initialsUFMG
local.url.externahttps://www.aanda.org/articles/aa/pdf/2023/08/aa46845-23.pdf

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