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dc.contributor.authorSchnerr, R.
dc.contributor.authorRygl, K.
dc.contributor.authorvan der Horst, A.
dc.contributor.authorOosterloo, T.
dc.contributor.authorMiller-Jones, James
dc.contributor.authorHenrichs, H.
dc.contributor.authorSpoelstra, T.
dc.contributor.authorFoley, A.
dc.identifier.citationSchnerr, R. and Rygl, K. and van der Horst, A. and Oosterloo, T. and Miller-Jones, J. and Henrichs, H. and Spoelstra, T. et al. 2007. Radio observations of candidate magnetic O stars. Astronomy and Astrophysics. 470 (3): pp. 1105-1109.

Context: Some O stars are suspected to have to have (weak) magnetic fields because of the observed cyclical variability in their UV wind-lines. However, direct detections of these magnetic fields using optical spectropolarimetry have proven to be very difficult.Aims: Non-thermal radio emission in these objects would most likely be due to synchrotron radiation. As a magnetic field is required for the production of synchrotron radiation, this would be strong evidence for the presence of a magnetic field. Such non-thermal emission has already been observed from the strongly magnetic Ap/Bp stars.Methods: We have performed 6 and 21 cm observations using the WSRT and use these, in combination with archival VLA data at 3.6 cm and results from the literature, to study the radio emission of 5 selected candidate magnetic O stars.Results: Out of our five targets, we have detected three: ? Per, which shows a non-thermal radio spectrum, and a Cam and ? Cep, which show no evidence of a non-thermal spectrum. In general we find that the observed free-free (thermal) flux of the stellar wind is lower than expected. This is in agreement with recent findings that the mass-loss rates from O stars as derived from the Ha line are overestimated because of clumping in the inner part of the stellar wind.

dc.publisherEDP Sciences
dc.subjectradiation mechanisms: non-thermal
dc.subjectstars: general
dc.subjectstars: mass-loss
dc.subjectstars: magnetic fields
dc.subjectradio continuum: stars
dc.subjectstars: early-type
dc.titleRadio observations of candidate magnetic O stars
dc.typeJournal Article
dcterms.source.titleAstronomy and Astrophysics
curtin.accessStatusFulltext not available

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