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Full-Text Articles in Physical Sciences and Mathematics

The Xmm-Newton Epic X-Ray Light Curve Analysis Of Wr 6., Richard Ignace, K. Gayley, W.-R. Hamann, D. Huenemoerder, L. Oskinova, A. Pollock, M. Mcfall Sep 2013

The Xmm-Newton Epic X-Ray Light Curve Analysis Of Wr 6., Richard Ignace, K. Gayley, W.-R. Hamann, D. Huenemoerder, L. Oskinova, A. Pollock, M. Mcfall

ETSU Faculty Works

We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the well-established 3.766 d period widely found at longer wavelengths. The data are of such quality that we were able to conduct a search for "event clustering" in the arrival times of X-ray photons. However, we fail to detect any such clustering. One possibility is that X-rays …


Faraday Rotation Distributions From Stellar Magnetism In Wind-Blown Bubbles., Richard Ignace, N. Pingel Mar 2013

Faraday Rotation Distributions From Stellar Magnetism In Wind-Blown Bubbles., Richard Ignace, N. Pingel

ETSU Faculty Works

Faraday rotation is a valuable tool for detecting magnetic fields. Here, the technique is considered in relation to wind-blown bubbles. In the context of spherical winds with azimuthal or split monopole stellar magnetic field geometries, we derive maps of the distribution of position angle (P.A.) rotation of linearly polarized radiation across projected bubbles. We show that the morphology of maps for split monopole fields are distinct from those produced by the toroidal field topology; however, the toroidal case is the one most likely to be detectable because of its slower decline in field strength with distance from the star. We …


A Report On The X-Ray Properties Of The Τ Sco Class Of Stars., Richard Ignace, L. Oskinova, D. Massa Feb 2013

A Report On The X-Ray Properties Of The Τ Sco Class Of Stars., Richard Ignace, L. Oskinova, D. Massa

ETSU Faculty Works

An increasing number of OB stars have been shown to possess magnetic fields. Although the sample remains small, it is surprising that the magnetic and X-ray properties of these stars appear to be far less correlated than expected. This contradicts model predictions, which generally indicate that the X-rays from magnetic stars are harder and more luminous than their non-magnetic counterparts. Instead, the X-ray properties of magnetic OB stars are quite diverse. τ Sco is one example where the expectations are better met. This bright main-sequence, early B star has been studied extensively in a variety of wavebands. It has a …


Investigating The Spectroscopic, Magnetic And Circumstellar Variability Of The O9 Subgiant Star Hd 57682., J. Grunhut, G. Wade, J. Sundqvist, A. Ud-Doula, C. Neiner, Richard Ignace, W. Marcolino, Th. Rivinius, A. Fullerton, L. Kaper, B. Mauclaire, C. Buil, T. Garrel, J. Ribeiro, S. Ubaud Jan 2013

Investigating The Spectroscopic, Magnetic And Circumstellar Variability Of The O9 Subgiant Star Hd 57682., J. Grunhut, G. Wade, J. Sundqvist, A. Ud-Doula, C. Neiner, Richard Ignace, W. Marcolino, Th. Rivinius, A. Fullerton, L. Kaper, B. Mauclaire, C. Buil, T. Garrel, J. Ribeiro, S. Ubaud

ETSU Faculty Works

The O9IV star HD 57682, discovered to be magnetic within the context of the Magnetism in Massive Stars (MiMeS) survey in 2009, is one of only eight convincingly detected magnetic O-type stars. Among this select group, it stands out due to its sharp-lined photospheric spectrum. Since its discovery, the MiMeS Collaboration has continued to obtain spectroscopic and magnetic observations in order to refine our knowledge of its magnetic field strength and geometry, rotational period and spectral properties and variability. In this paper we report new Echelle SpectroPolarimetric Device for the Observation of Stars (ESPaDOnS) spectropolarimetric observations of HD 57682, which …


Discovery Of A Magnetic Field In The Rapidly-Rotating O-Type Secondary Of The Colliding-Wind Binary Hd 47129 (Plaskett’S Star)., J. Grunhut, G. Wade, M. Leutenegger, V. Petit, G. Rauw, C. Neiner, F. Martins, D. Cohen, M. Gagné, Richard Ignace, S. Mathis, S. De Mink, A. Moffat, S. Owocki, M. Shultz, J. Sundqvist, Mimes Collaboration Jan 2013

Discovery Of A Magnetic Field In The Rapidly-Rotating O-Type Secondary Of The Colliding-Wind Binary Hd 47129 (Plaskett’S Star)., J. Grunhut, G. Wade, M. Leutenegger, V. Petit, G. Rauw, C. Neiner, F. Martins, D. Cohen, M. Gagné, Richard Ignace, S. Mathis, S. De Mink, A. Moffat, S. Owocki, M. Shultz, J. Sundqvist, Mimes Collaboration

ETSU Faculty Works

We report the detection of a strong, organized magnetic field in the secondary component of the massive O8III/I+O7.5V/III double-lined spectroscopic binary system HD 47129 (Plaskett's star) in the context of the Magnetism in Massive Stars survey. Eight independent Stokes V observations were acquired using the Echelle SpectroPolarimetric Device for the Observations of Stars (ESPaDOnS) spectropolarimeter at the Canada–France–Hawaii Telescope and the Narval spectropolarimeter at the Télescope Bernard Lyot. Using least-squares deconvolution we obtain definite detections of signal in Stokes V in three observations. No significant signal is detected in the diagnostic null (N) spectra. The Zeeman signatures are broad and …