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dc.contributor.authorPestalozzi, M.
dc.contributor.authorBenz, A.O.
dc.contributor.authorConway, J.
dc.contributor.authorGudel, M.
dc.date.accessioned2007-12-19T11:53:59Z
dc.date.available2007-12-19T11:53:59Z
dc.date.issued2000
dc.identifier.citationPestalozzi , M , Benz , A O , Conway , J & Gudel , M 2000 , ' VLBI observations of two single dMe stars: spatial resolution and astrometry ' , Astronomy and Astrophysics , vol. 353 , pp. 569-574 .
dc.identifier.issn1432-0746
dc.identifier.otherPURE: 140924
dc.identifier.otherPURE UUID: 4a1a325a-56ca-4e9b-97ac-fbf3228a14a7
dc.identifier.otherdspace: 2299/1241
dc.identifier.otherScopus: 4243615170
dc.identifier.urihttp://hdl.handle.net/2299/1241
dc.description.abstractWe report on 3.6 cm VLA and VLBA observations of YZ CMi and AD Leo, two nearby dMe stars. We resolve YZ CMi and can fit a circular symmetrical gaussian component of FWHP of 0.98 0.2 mas, corresponding to an extent of the corona above the photosphere of 1:77 1010 8:8 109 cm or 0.7 0:3 R? (R? refers to the photospheric radius). We obtain an estimate of the brightness temperature of 7:3 107 K, which is consistent with that expected from gyrosynchrotron emission. For AD Leo the emitting region is unresolved. We therefore set a conservative upper limit to its diameter of 1.8 times the photosphere diameter, which leads to an extent of the corona above the photosphere of < 2:8 1010cm or < 0:8 R?. We compare the radio emitting dMe stars with measured sizes with the Sun and conclude that these active stars have much more extended coronal radio emission than the Sun. The VLBA position of YZ CMi has been found to differ by 32 mas from the positions calculated from the Hipparcos catalogue. The discrepancy is caused by large errors in the listed proper motion. An improved value is given.en
dc.language.isoeng
dc.relation.ispartofAstronomy and Astrophysics
dc.titleVLBI observations of two single dMe stars: spatial resolution and astrometryen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.description.statusPeer reviewed
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue


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