相关论文: Pulsations and outbursts in Be stars: Small differ…

Variable B supergiants (BSGs) constitute a heterogeneous group of stars with complex photometric and spectroscopic behaviours. They exhibit mass-loss variations and experience different types of oscillation modes, and there is growing…

The tidal interaction of a Be star with a binary companion forms two spiral arms that cause orbital modulation of the Be disc structure. The aim of this work is to identify observables in which this modulation is apparent. The structure of…

Stars are generally spherical, yet their gaseous envelopes often appear non-spherical when ejected near the end of their lives. This quirk is most notable during the planetary nebula phase when these envelopes become ionized. Interactions…

Subdwarf B stars show chemical peculiarities that cannot be explained by diffusion theory alone. Both mass loss and turbulence have been invoked to slow down atomic diffusion in order to match observed abundances. The fact that some sdB…

To study the variability of the 523 B and Be stars observed in the Magellanic clouds with the VLT-FLAMES, we cross-matched the stars of our sample with the photometric database MACHO, which provides for each star an 8 years lightcurve. We…

Be stars are rapidly rotating, with angular frequency around $0.7-0.8$ of their Keplerian break up frequency, as a result of significant accretion during the earlier stellar evolution of a companion star. Material from the equator of the Be…

Several classes of stars (most notably O and B main-sequence stars, as well as accreting white dwarfs and neutron stars) rotate quite rapidly, at spin frequencies greater than the typical g-mode frequencies. We discuss how rapid rotation…

Evolved stars dominate galactic spectra, enrich the galactic medium, expand to change their planetary systems, eject winds of a complex nature, produce spectacular nebulae and illuminate them, and transfer material between binary…

Stellar variability may originate from various phenomena such as binarity, pulsations, or rotation. These mechanisms can induce flux variations of similar magnitudes, shapes, and periods. We aim to determine mechanisms responsible for the…

Pulsation period changes in Mira type variables are investigated using the stellar evolution and nonlinear stellar pulsation calculations. We considered the evolutionary sequence of stellar models with initial mass 3 Msol and population I…

The Be star 102719279 is an interesting target observed with CoRoT during two runs, giving us the possibility to study the stability of the detected frequencies and to search for any correlation with outburts, as it was recently found in…

In most Delta Scuti stars, the measured period changes are considerably larger than those expected from stellar evolution. In order to study these period and amplitude changes, a few selected stars are measured photometrically for hundreds…

Be X-ray binaries are among the best known transient high-energy sources. Their outbursts are commonly classified into a simple scheme of 'normal' and 'giant' outbursts, but a closer look shows that actual outbursts do not always follow…

Some Ap stars with strong magnetic fields pulsate in high order p-modes; they are called roAp (rapidly oscillating Ap) stars. The p-mode frequencies are modified by the magnetic fields. Although the large frequency separations are hardly…

We use the traditional approximation to describe oscillations with frequencies comparable to the angular rotation rate. Validity of this approximation in application to main-sequence B stars is discussed. Numerical results regarding mode…

Recent dramatic improvements in the modeling of abundance evolution due to diffusion in A stars have been achieved with the help of monochromatic opacity tables from the OPAL group. An important result in the context of stellar pulsations…

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…

The MOST (Microvariability and Oscillations of Stars) satellite has discovered SPBe (Slowly Pulsating Be) oscillations in the stars HD 127756 (B1/B2 Vne) and HD 217543 (B3 Vpe). For HD 127756, 30 significant frequencies are identified from…

We study the gravitational radiation associated to the non--radial oscillations of newly born, hot neutron stars. The frequencies and damping times of the relevant quasi--normal modes are computed for two different models of proto--neutron…

We present the results of a ROSAT Position Sensitive Proportional Counter observation of the variable radio star \ls. The source has a power law spectrum with photon index 1.1 +/- 0.3 and a luminosity of 5.9 x 10^{33} erg/s in the 0.1 -2.4…