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Precessing planetary magnetospheres in SiO stars ? First detection of quasi-periodic polarization fluctuations in R Leo and V Cam

hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
dc.contributor.authorWIESEMEYER, Helmut W.
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
dc.contributor.authorTHUM, Clemens
hal.structure.identifierFORMATION STELLAIRE 2009
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
hal.structure.identifierUniversité Sciences et Technologies - Bordeaux 1 [UB]
dc.contributor.authorBAUDRY, Alain
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
hal.structure.identifierUniversité Sciences et Technologies - Bordeaux 1 [UB]
hal.structure.identifierFORMATION STELLAIRE 2009
dc.contributor.authorHERPIN, Fabrice
dc.date.created2008
dc.date.issued2009
dc.identifier.issn0004-6361
dc.description.abstractEnThe origin of magnetism around AGB stars is uncertain. If these stars drive a dynamo, it cannot be sufficient to generate a strong global field, otherwise the observed X-ray luminosities would be higher. Other explanations for the circular polarization of SiO masers in the atmospheres are needed. The interaction of the AGB wind with previously ejected matter and with planets bears complex magneto-hydrodynamic phenomena on a short time scale, such that strong magnetic fields can be maintained locally. Here we provide observational evidence for the corresponding magnetic fluctuations. We trace magnetic activity with the circular polarization of the v=1, J=2-1 SiO masers, using a correlation polarimeter. In V Cam and R Leo, we find evidence of pseudo-periodic fluctuations of the circular polarization on a timescale of a few hours, from which we infer magnetic fluctuations of ~1G. The phenomenon is rare and restricted to a narrow range of velocities. It seems to be associated with planetary wake flows suggested by VLBI maps. While scenarios involving magnetic activity in the extended stellar atmosphere have problems to explain all observed features, precessing Jovian magnetospheres predict all of them. For the case of R Leo, we constrain the orbit of the planet (estimated period 5.2 years) and estimate a stellar mass of 0.7 solar masses.
dc.language.isoen
dc.publisherEDP Sciences
dc.title.enPrecessing planetary magnetospheres in SiO stars ? First detection of quasi-periodic polarization fluctuations in R Leo and V Cam
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361/200811242
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO]
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]
dc.identifier.arxiv0809.0359
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.page801-810
bordeaux.volume498
bordeaux.issue3
bordeaux.peerReviewedoui
hal.identifierhal-00315778
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00315778v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Astronomy%20and%20Astrophysics%20-%20A&A&rft.date=2009&rft.volume=498&rft.issue=3&rft.spage=801-810&rft.epage=801-810&rft.eissn=0004-6361&rft.issn=0004-6361&rft.au=WIESEMEYER,%20Helmut%20W.&THUM,%20Clemens&BAUDRY,%20Alain&HERPIN,%20Fabrice&rft.genre=article


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