Related papers: Semiregular variable stars
Context: [abbreviated] Aims: Kepler data of three known Be stars are re-visited to establish their pulsational nature and assess the properties of additional, non-pulsational variations. The three program stars turned out to be one inactive…
The Slowly Pulsating B-type (SPB) stars are the upper main-sequence stars on the HR diagram. Their oscillations are high-order, low-degree g-mode and can be used to probe the structure of the radiative zone where is near the outer boundary…
We present time series photometry of 57 variable stars in the cluster region NGC 7380. The association of these variable stars to the cluster NGC 7380 has been established on the basis of two colour diagrams and colour-magnitude diagrams.…
Anomalous Cepheids are a rather rare family of pulsating variables preferably found in dwarf galaxies. Attempts to model these variable stars via single-star evolution scenarios still leave space for improvements to better grasp their…
A thorough analysis of the OGLE-II time-series photometry of the Large Magellanic Cloud bar supplemented by similar data from the MACHO database led us to the discovery of three Beta Cephei-type stars. These are the first known…
Classical variables like RR Lyrae, classical and Type-II Cepheids and Mira variables all follow period-luminosity relations that make them interesting as distance indicators. Especially the RR Lyrae and delta Cepheids are crucial in…
We present a detailed lightcurve analysis for a sample of bright semiregular variables based on long-term (70--90 years) visual magnitude estimates carried out by amateur astronomers. Fundamental changes of the physical state (amplitude…
We present an analysis of the nature of the rapidly rotating, apparently single giant based on rotational and radial velocity measurements carried out by the CORAVEL spectrometers. From the analyzed sample, composed of 2010 spectroscopic,…
Massive stars are essential to understand a variety of branches of astronomy including galaxy and star cluster evolution, nucleosynthesis and supernovae, pulsars and black holes. It has become evident that massive star evolution is very…
Based on their stellar parameters and the presence of a mid-IR excess due to circumstellar dust, RV Tauri stars have been classified as post-AGB stars. Our recent studies, however, reveal diverse SEDs among RV Tauri stars, suggesting they…
Strange modes have been found in the radial spectrum of many luminous stars, most recently in Cepheids and RR Lyrae. We show that there is nothing strange about these modes -- they must exist even in the adiabatic limit. With a change of…
V CVn is a semiregular variable star with a V-band amplitude of $\approx2$ mag. This star has an unusually high amplitude of polarimetric variability: up to 6 per cent. It also exhibits a prominent inverse correlation between the flux and…
The progenitors of Type IIP supernovae have an apparent upper limit to their initial masses of about 20 solar masses, suggesting that the most massive red supergiants evolve to warmer temperatures before their terminal explosion. But very…
Very massive stars occasionally expel material in colossal eruptions, driven by continuum radiation pressure rather than blast waves. Some of them rival supernovae in total radiative output, and the mass loss is crucial for subsequent…
TESS observations of pulsating hot main sequence stars paint a very different picture from what is currently accepted. There are large numbers of delta Scuti (DSCT) stars hotter than the theoretical hot edge of the instability strip,…
I review recent progress on understanding eruptions of unstable massive stars, with particular attention to the diversity of observed behavior in extragalatic optical transient sources that are generally associated with giant eruptions of…
Over the past several decades, time-series photometry of CSPNe has yielded significant results including, but not limited to, discoveries of nearly 100 binary systems, insights into pulsations and winds in young white dwarfs, and studies of…
An overview of pulsating variable stars across the observational Hertzprung-Russel (HR) diagram is presented, together with a summary of their global properties. The HR diagram is presented with a third colour-coded dimension, visualizing…
Luminous blue variables are an intermediate stage in the evolution of high-mass stars characterized by extreme mass loss and substantial variability. The stars show large irregular episodic variations on timescales of years to decades in…
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…