Related papers: X-rays from Hot Subdwarfs
We present the results of XMM-Newton X-ray observations of the Mira AB binary system, which consists of a pulsating, asymptotic giant branch primary and nearby (~0.6'' separation) secondary of uncertain nature. The EPIC CCD (MOS and pn)…
X-ray emission from stars has origins as diverse as the stars themselves: accretion shocks, shocks generated in wind-wind collisions, or release of magnetic energy. Although the scenarios responsible for X-ray emission are thought to be…
X-ray polarimetry is a fine tool to probe the accretion geometry and physical processes operating in the proximity of compact objects, black holes and neutron stars. Recent discoveries made by the Imaging X-ray Polarimetry Explorer put our…
The most favored interpretation for the detection of X-ray emission from late B-type stars is that these stars have a yet undiscovered late-type companion (or an unbound nearby late-type star) that produces the X-rays. Several faint IR…
The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with…
The supersonic stellar and disk winds possessed by massive young stellar objects will produce shocks when they collide against the interior of a pre-existing bipolar cavity (resulting from an earlier phase of jet activity). The shock heated…
A decade of X-ray stellar observations with Chandra and XMM-Newton has led to significant advances in our understanding of the physical processes at work in hot (magnetized) plasmas in stars and their immediate environment, providing new…
A growing number of early Be stars discovered in X-ray surveys exhibit X-ray luminosities intermediate between those of normal stars and those of most Be/X-ray binaries in quiescence. Their X-ray spectra are also much harder than those of…
X-ray properties of the stellar population in the Carina OB1 association are examined with special emphasis on early-type stars. Their spectral characteristics provide some clues to understanding the nature of X-ray formation mechanisms in…
We review the current status of studies of disc atmospheres and winds in low mass X-ray binaries. We discuss the possible wind launching mechanisms and compare the predictions of the models with the existent observations. We conclude that a…
One of the main properties of Wolf-Rayet (WR) stars is a very intense outflow of gas. No less than 40\% \ of WR stars belong to binary systems. Young massive O and B stars are the secondary components of such systems. OB stars also have an…
Recent X-ray observations have revealed the complexity and diversity of high-mass X-ray binaries (HMXBs). This diversity challenges a classical understanding of the accretion process onto the compact objects. In this study, we reinforce the…
It has been suggested that most Be/X-ray binaries are low X-ray luminosity nearby objects, containing white dwarfs (Chevalier & Ilovaisky 1998). We show that existing evidence indicates that all known Be/X-ray binaries are relatively bright…
The accretion-induced collapse (AIC) of a white dwarf in a binary with a nondegenerate companion can sometimes lead to the formation of a rapidly rotating and highly magnetized neutron star (NS). The spin-down of this NS can drive a…
The origin of the bright and hard X-ray emission flux among the gamma Cas subgroup of B-emission line (Be) stars may be caused by gas accretion onto an orbiting white dwarf (WD) companion. Such Be+WD binaries are the predicted outcome of a…
We have developed a clumpy stellar wind model for OB supergiants in order to compare predictions of this model with the X-ray behaviour of both classes of persistent and transient High Mass X-ray Binaries (HMXBs).
Massive X-ray binaries are formed by a compact object that accretes matter from the stellar wind of an early-type donor star. In some of these systems, called microquasars, relativistic jets are launched from the surroundings of the compact…
The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with…
Bright and eclipsing, the high-mass X-ray binary Vela X-1 offers a unique opportunity to study accretion onto a neutron star from clumpy winds of O/B stars and to disentangle the complex accretion geometry of these systems. In Chandra-HETGS…
Simultaneous multiwavelength studies of X-ray binaries have been remarkably successful and resulted in improved physical constraints, a new understanding of the dependence of mass accretion rate on X-ray state, as well as insights on the…