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A review of spectroscopic results obtained from Chandra High Energy Transmission Grating Spectrometer and XMM-Newton Reflection Grating Spectrometer observations of several wind-fed high-mass X-ray binaries (HMXBs) is presented. These…

Astrophysics · Physics 2007-05-23 M. Sako , S. M. Kahn , F. Paerels , D. A. Liedahl , S. Watanabe , F. Nagase , T. Takahashi

We derive basic stellar parameters (angular diameters, effective temperatures, metallicities) and interstellar reddening for all beta Cephei stars observed during the IUE satellite mission, including those belonging to three open clusters.…

Astrophysics · Physics 2009-11-10 E. Niemczura , J. Daszynska-Daszkiewicz

Recently Neiner et al. reported that the B2 IV-V star zeta Cas contains a weak magnetic field which varies on the same 5.37 day period found from the modulations of its N V, C IV, and Si IV UV resonance lines. We have studied the time…

Astrophysics · Physics 2009-11-13 Myron A. Smith , David A. Bohlender

We present for the first time phase-resolved UV spectroscopy of an Of?p star, namely, HD 191612. The observations were acquired with the Space Telescope Imaging Spectrograph (STIS) on-board the Hubble Space Telescope (HST). We report the…

Solar and Stellar Astrophysics · Physics 2015-06-15 W. L. F. Marcolino , J. -C. Bouret , J. O. Sundqvist , N. R. Walborn , A. W. Fullerton , I. D. Howarth , G. A. Wade , A. ud-Doula

We present two dimensional cylindrically symmetric hydrodynamic simulations and synthetic emission maps of a stellar wind propagating into an infalling, rotating environment. The resulting outflow morphology, collimation and stability…

We present new wind models for {\tau} Bo\"otis ({\tau} Boo), a hot-Jupiter-host-star whose observable magnetic cycles makes it a uniquely useful target for our goal of monitoring the temporal variability of stellar winds and their…

Solar and Stellar Astrophysics · Physics 2016-11-15 B. A. Nicholson , A. A. Vidotto , M. Mengel , L. Brookshaw , B. Carter , P. Petit , S. C. Marsden , S. V. Jeffers , R. Fares , the BCool Collaboration

We examine the angular momentum loss and associated rotational spindown for magnetic hot stars with a line-driven stellar wind and a rotation-aligned dipole magnetic field. Our analysis here is based on our previous 2-D numerical MHD…

Astrophysics · Physics 2009-11-13 Asif ud-Doula , Stanley P. Owocki , Richard H. D. Townsend

We use two-dimensional axisymmetric magnetohydrodynamic simulations to compute steady-state solutions for solar-like stellar winds from rotating stars with dipolar magnetic fields. Our parameter study includes 50 simulations covering a wide…

Solar and Stellar Astrophysics · Physics 2015-06-05 Sean P. Matt , Keith B. MacGregor , Marc H. Pinsonneault , Thomas P. Greene

In this work, we simulate the evolution of the solar wind along its main sequence lifetime and compute its thermal radio emission. To study the evolution of the solar wind, we use a sample of solar mass stars at different ages. All these…

Solar and Stellar Astrophysics · Physics 2019-06-17 D. Ó Fionnagáin , A. A. Vidotto , P. Petit , C. P. Folsom , S. V. Jeffers , S. C. Marsden , J. Morin , J. -D. do Nascimento

The growth of spectroscopic observations of exoplanetary systems allows the possibility of testing theoretical models and studying the interaction that exoplanetary atmospheres have with the wind and the energetic photons from the star. In…

Earth and Planetary Astrophysics · Physics 2020-09-30 C. Villarreal D'Angelo , A. A. Vidotto , A. Esquivel , M. A. Sgró , T. Koskinen , L. Fossati

We investigate the possibility that a magnetic field may be present in the star $o-$Ceti (hereafter, Mira) and that the field plays a role in the star's mass loss. The model presented here is an application of an earlier derived theory that…

Solar and Stellar Astrophysics · Physics 2014-06-11 Anand Thirumalai , Jeremy S. Heyl

Aims. In this study, we analyse the magnetic field properties of a set of 15 global magnetohydrodynamics (MHD) simulations of solar-type star dynamos conducted using the ASH code. Our objective is to enhance our understanding of these…

Solar and Stellar Astrophysics · Physics 2024-02-14 Quentin Noraz , Allan Sacha Brun , Antoine Strugarek

Investigation of propagation, conversion, and scattering of MHD waves in the Sun is very important for understanding the mechanisms of observed oscillations and waves in sunspots and active regions. We have developed 3D linear MHD numerical…

Astrophysics · Physics 2011-02-11 K. V. Parchevsky , A. G. Kosovichev

A number of O stars are suspected to have (weak) magnetic fields because of the observed cyclical variability in their UV wind-lines. However, direct detections of these magnetic fields with optical spectropolarimetry have proven to be very…

The magnetic field of CPD -57 3509 was recently detected in the framework of the BOB (B fields in OB stars) collaboration. We acquired low-resolution spectropolarimetric observations of CPD -57 3509 with FORS2 and high-resolution UVES…

We review current theoretical ideas on pulsar winds and their surrounding nebulae. Relativistic MHD models of the wind of the aligned rotator, and of the striped wind, together with models of magnetic dissipation are discussed. It is shown…

Astrophysics · Physics 2015-06-24 J. G. Kirk , Y. Lyubarsky , J. Petri

The study of the X-ray line profiles produced by massive colliding wind binaries is a powerful tool for the characterisation of the stellar winds. We built a self-consistent program for the computation of line profiles named LIFELINE. The…

Instrumentation and Methods for Astrophysics · Physics 2021-02-17 E. Mossoux , G. Rauw

3D-MHD numerical simulations of bipolar, hypersonic, weakly magnetized jets and synthetic synchrotron observations are presented to study the structure and evolution of magnetic fields in FR II radio sources. The magnetic field setup in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Martin Huarte-Espinosa , Martin Krause , Paul Alexander

A method for the asteroseismic analysis of beta Cephei stars is presented and applied to the star nu Eridani. The method is based on the analysis of rotational splittings, and their asymmetries using differentially-rotating asteroseismic…

Astrophysics · Physics 2011-02-11 J. C. Suarez , A. Moya , P. J. Amado , S. Martin-Ruiz , C. Rodriguez-Lopez , R. Garrido

A small fraction of the radiative flux emitted by hot stars is absorbed by their winds and redistributed towards longer wavelengths. This effect, which leads also to the heating of the stellar photosphere, is termed wind blanketing. For…

Solar and Stellar Astrophysics · Physics 2018-10-03 J. Krticka , A. Feldmeier