Related papers: Oscillations in Procyon A: First results from a mu…
The interplay between radiative diffusion, rotation, convection, and magnetism in metallic-line chemically peculiar stars is still not fully understood. Recently, evidence has emerged that these effects can work together. Our goal is to…
Periodic increases in luminosity arising from variable accretion rates have been predicted for some close pre-main sequence binary stars as they grow from circumbinary disks. The phenomenon is known as "pulsed accretion" and can affect the…
We present 18 years of OGLE photometry together with spectra obtained over 12 years, revealing that the early Oe star AzV 493 shows strong photometric (Delta I < 1.2 mag) and spectroscopic variability with a dominant, 14.6-year pattern and…
Parameter regions in which stars can become pulsationally unstable are found throughout the Hertzsprung-Russel diagram. Stars of high, intermediate, low and very low masses may cross various instability regions along their paths of…
Convection in stars excites resonant acoustic waves. The frequencies of these oscillations depend on the sound speed inside the star, which in turn depends on density, temperature, gas motion, and other properties of the stellar interior.…
Context. In previous work, we studied a prominence which appeared like a tornado in a movie made from 193 {\AA} filtergrams obtained with the Atmospheric Imaging Assembly (AIA) imager aboard the Solar Dynamics Observatory (SDO). The…
We compare evolved stellar models, which match Procyons mass and position in the HR diagram, to current ground-based asteroseismic observations. Diffusion of helium and metals along with two conventional core overshoot descriptions and the…
We report the detection with the Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) of 530 Hz burst oscillations in a thermonuclear (type I) burst from the transient X-ray source A1744-361. This is only the second burst…
Rapidly oscillating Ap stars are unique objects in the potential they offer to study the interplay between a number of important physical phenomena, in particular, pulsations, magnetic fields, diffusion, and convection. Nevertheless, the…
The pulsating eclipsing binaries are remarkable systems that provide an opportunity to probe the stellar interior and to determine the fundamental stellar parameters precisely. Especially the detached eclipsing binary systems with (a)…
More than 40 years of ground-based photometric observations of the delta Sct star 4CVn revealed 18 independent oscillation frequencies, including radial as well as non-radial p-modes of low spherical degree l<=2. From 2008 to 2011, more…
V Hya, an evolved carbon star with a complex circumstellar envelope, has two variability periods, 530d and 6000d (17 years). We analyze recent light curve data and show that both variations have benn present for at least 100 years and have…
Broadening and asymmetry of spectral lines in slowly rotating late A-type stars provide evidence for high-amplitude convective motions. The properties of turbulence observed in the A-star atmospheres are not understood theoretically and…
It has been shown that a discontinuity in the derivatives of the sound speed at the edge of the convective regions inside a star gives rise to a characteristic oscillatory signal in the frequencies of stellar oscillations. This oscillatory…
We study the brightness variations of galactic red supergiant stars using long-term visual light curves collected by the American Association of Variable Star Observers (AAVSO) over the last century. The full sample contains 48 red…
Convection is ubiquitous in stars and occurs under many different conditions. Here we explore convection in main-sequence stars through two lenses: dimensionless parameters arising from stellar structure and parameters which emerge from the…
We present the first results from the Transiting Exoplanet Survey Satellite (TESS) on the rotational and pulsational variability of magnetic chemically peculiar A-type stars. We analyse TESS 2-min cadence data from sectors 1 and 2 on a…
We present an analysis of eleven years of Stromgren by photometry of the red semiregular variable star AI Aurigae. An early period determination of 63.9 days is confirmed by the long-term light curve behaviour. The light curve shows…
We have made a clear detection of p-mode oscillations in the nearest solar-like G2V star $\alpha$ Cen A with the CORALIE spectrograph on the 1.2-m Swiss telescope at the ESO La Silla Observatory. We report the 5 nights of observation on…
Stellar radio emission can measure a star's magnetic field strength and structure, plasma density and dynamics, and the stellar wind pressure impinging on exoplanet atmospheres. However, properly interpreting the radio data often requires…