Related papers: "Stellar Prominences" on OB stars to explain wind-…
We present the analysis of a multi-epoch spectroscopic monitoring campaign of the O6Ief star lambda Cep. Previous observations reported the existence of two modes of non-radial pulsations in this star. Our data reveal a much more complex…
Recent re-determination of stellar atmospheric parameters for a sample of stars observed during the {\it Kepler} mission allowed to enlarge the number of {\it Kepler} B-type stars. We present the detailed frequency analysis for all these…
Examination of the temporal variability properties of several strong optical recombination lines in a large sample of Galactic Wolf-Rayet (WR) stars reveals possible trends, especially in the more homogeneous WC than the diverse WN…
The long-time photometric surveys in a few young open clusters allowed to identify the light variability in stars located on the HR diagram between the well defined $\delta$ Scuti variables and Slowly Pulsating B-type stars. Several objects…
Recent studies of massive O-type stars present clear evidences of inhomogeneous and clumped winds. O-type (H-rich) central stars of planetary nebulae (CSPNs) are in some ways the low mass-low luminosity analogous of those massive stars. In…
Massive stars exhibit spectroscopic and photometric variability over a wide range of timescales. However the physical mechanisms driving this behaviour remain poorly understood. Westerlund 1 presents an ideal laboratory for studying these…
UV wind line variability in OB stars appears to be universal. To quantify this variation and to estimate its effect on a mass loss rate determined from a single observation, we use the IUE archive to identify non-peculiar OB stars with well…
Subdwarf B (sdB) stars form the blue end of the horizonal branch. Their peculiar atmospheric abundance patterns are due to diffusion processes. However, diffusion models fail to explain these anomalies quantitatively. From a NLTE model…
The clumping of massive star winds is an established paradigm, which is confirmed by multiple lines of evidence and is supported by stellar wind theory. We use the results from time-dependent hydrodynamical models of the instability in the…
We study the stellar and wind properties of a sample of Galactic O dwarfs to track the conditions under which weak winds (i.e mass loss rates lower than ~ 1e-8 Msol/yr) appear. The sample is composed of low and high luminosity dwarfs…
Magnetic fields have been frequently invoked as a likely source of variability and confinement of the winds of massive stars. To date, the only magnetic field detected in O-type stars are those of theta 1 Ori C (HD 37022; Donati et al.…
Winds of massive stars are an important ingredient in determining their evolution, final remnant mass, and feedback to the surrounding interstellar medium. We compare empirical results for OB star winds at low metallicity with theoretical…
Massive stars are crucial building blocks of galaxies and the universe, as production sites of heavy elements and as stirring agents and energy providers through stellar winds and supernovae. The field of magnetic massive stars has seen…
We present a study of the kinematical properties of a small sample of nearby near-infrared bright massive and intermediate mass young stellar objects using emission lines sensitive to discs and winds. We show for the first time that the…
Spectral-line displacements away from the wavelengths naively expected from the Doppler shift caused by stellar radial motion may originate as convective shifts (correlated velocity and brightness patterns in the photosphere), as…
In some massive stars, magnetic fields are thought to confine the outflowing radiatively-driven wind. Although theoretical models and MHD simulations are able to illustrate the dynamics of such a magnetized wind, the impact of this…
The star zeta Ophiuchi is one of the brightest massive stars in the northern hemisphere and was intensively studied in various wavelength domains. The currently available observational material suggests that certain observed phenomena are…
Stellar photometric variability offers a novel probe of the interior structure and evolutionary state of stars. Here we present a census of stellar variability on day to decade timescales across the color-magnitude diagram for 73,000 stars…
Early-type B stars with strong magnetic fields and rapid rotation form centrifugal magnetospheres (CMs), as the relatively weak stellar wind becomes magnetically confined and centrifugally supported above the Kepler co-rotation radius. CM…
Magnetic B-type stars exhibit photometric variability due to diverse causes, and consequently on a variety of timescales. In this paper we describe interpretation of BRITE photometry and related ground-based observations of 4 magnetic…