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Full-Text Articles in Stars, Interstellar Medium and the Galaxy
Early Magnetic B-Type Stars: X-Ray Emission And Wind Properties., L. M. Oskinova, H. Todt, R. Ignace, J. C. Brown, J. P. Cassinelli, W.-R. Hamann
Early Magnetic B-Type Stars: X-Ray Emission And Wind Properties., L. M. Oskinova, H. Todt, R. Ignace, J. C. Brown, J. P. Cassinelli, W.-R. Hamann
Richard Ignace
We present a comprehensive study of X-ray emission by, and wind properties of, massive magnetic early B-type stars. Dedicated XMM–Newton observations were obtained for three early-type B-type stars, ξ1 CMa, V2052 Oph and ζ Cas, with recently discovered magnetic fields. We report the first detection of X-ray emission from V2052 Oph and ζ Cas. The latter is one the softest X-ray sources among the early-type stars, while the former is one of the X-ray faintest. The observations show that the X-ray spectra of our programme stars are quite soft with the bulk of X-ray emitting material having a temperature …
Time-Dependent Behavior Of Linear Polarization In Unresolved Photospheres, With Applications For The Hanle Effect., R. Ignace, K. T. Hole, J. P. Cassinelli, G. D. Henson
Time-Dependent Behavior Of Linear Polarization In Unresolved Photospheres, With Applications For The Hanle Effect., R. Ignace, K. T. Hole, J. P. Cassinelli, G. D. Henson
Richard Ignace
Aims: This paper extends previous studies in modeling time varying linear polarization due to axisymmetric magnetic fields in rotating stars. We use the Hanle effect to predict variations in net line polarization, and use geometric arguments to generalize these results to linear polarization due to other mechanisms. Methods: Building on the work of Lopez Ariste et al., we use simple analytic models of rotating stars that are symmetric except for an axisymmetric magnetic field to predict the polarization lightcurve due to the Hanle effect. We highlight the effects for the variable line polarization as a function of viewing inclination and …
Discovery Of The First Τ Sco Analogues: Hd 66665 And Hd 63425., V. Petit, D. L. Massa, W. L. F. Marcolinino, G. A. Wade, R. Ignace
Discovery Of The First Τ Sco Analogues: Hd 66665 And Hd 63425., V. Petit, D. L. Massa, W. L. F. Marcolinino, G. A. Wade, R. Ignace
Richard Ignace
The B0.2 V magnetic star τ Sco stands out from the larger population of massive OB stars due to its high X-ray activity, peculiar wind diagnostics and highly complex magnetic field. This Letter presents the discovery of the first two τ Sco analogues – HD 66665 and HD 63425, identified by the striking similarity of their ultraviolet (UV) spectra to that of τ Sco. ESPaDOnS spectropolarimetric observations were secured by the Magnetism in Massive Stars CFHT Large Program, in order to characterize the stellar and magnetic properties of these stars. cmfgen modelling of optical ESPaDOnS spectra and archived IUE UV …
Early Magnetic B-Type Stars: X-Ray Emission And Wind Properties, Lidia Oskinova, Helge Todt, Richard Ignace, John Brown, Joseph Cassinelli, Wolf-Rainer Hamann
Early Magnetic B-Type Stars: X-Ray Emission And Wind Properties, Lidia Oskinova, Helge Todt, Richard Ignace, John Brown, Joseph Cassinelli, Wolf-Rainer Hamann
Richard Ignace
We present a comprehensive study of X-ray emission and wind properties of magnetic early B-type stars. We compile the complete sample of early B-type stars with detected magnetic fields to date and existing X-ray measurements, in order to study whether the X-ray emission can be used as a general proxy for stellar magnetism. For the first time we analyze the UV spectra of B stars with magnetic fields by means of non-LTE iron-blanketed stellar atmosphere model that account for the X-rays at the intensity and temperatures observed. The mass-loss rates inferred from the analysis of UV lines are significantly lower …