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Full-Text Articles in Physical Sciences and Mathematics
X-Ray Emission Line Profiles From Wind Clump Bow Shocks In Massive Stars., R. Ignace, W. Waldron, J. Cassinelli, A. Burke
X-Ray Emission Line Profiles From Wind Clump Bow Shocks In Massive Stars., R. Ignace, W. Waldron, J. Cassinelli, A. Burke
ETSU Faculty Works
The consequences of structured flows continue to be a pressing topic in relating spectral data to physical processes occurring in massive star winds. In a preceding paper, our group reported on hydrodynamic simulations of hypersonic flow past a rigid spherical clump to explore the structure of bow shocks that can form around wind clumps. Here we report on profiles of emission lines that arise from such bow shock morphologies. To compute emission line profiles, we adopt a two-component flow structure of wind and clumps using two “beta” velocity laws. While individual bow shocks tend to generate double-horned emission line profiles, …
Early Magnetic B-Type Stars: X-Ray Emission And Wind Properties., L. Oskinova, H. Todt, Richard Ignace, J. Brown, J. Cassinelli, W.-R. Hamann
Early Magnetic B-Type Stars: X-Ray Emission And Wind Properties., L. Oskinova, H. Todt, Richard Ignace, J. Brown, J. Cassinelli, W.-R. Hamann
ETSU Faculty Works
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 of …
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
ETSU Faculty Works
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 …
Discovery Of X-Ray Emission From The Wolf-Rayet Star Wr 142 Of Oxygen Subtype., L. Oskinova, W.-R. Hamann, A. Feldmeier, Richard Ignace, Y.-H. Chu
Discovery Of X-Ray Emission From The Wolf-Rayet Star Wr 142 Of Oxygen Subtype., L. Oskinova, W.-R. Hamann, A. Feldmeier, Richard Ignace, Y.-H. Chu
ETSU Faculty Works
We report the discovery of weak yet hard X-ray emission from the Wolf-Rayet (WR) star WR 142 with the XMM-Newton X-ray telescope. Being of spectral subtype WO2, WR 142 is a massive star in a very advanced evolutionary stage shortly before its explosion as a supernova or gamma-ray burst. This is the first detection of X-ray emission from a WO-type star. We rule out any serendipitous X-ray sources within approximate to 1 '' of WR 142. WR 142 has an X-ray luminosity of L(X) approximate to 7 x 10(30) erg s(-1), which constitutes only less than or similar to 10(-8) …