Related papers: Variable stars across the observational HR diagram
Many astrophysical phenomena are time-varying, in the sense that their brightness change over time. In the case of periodic stars, previous approaches assumed that changes in period, amplitude, and phase are well described by either…
The Hertzsprung-Russell diagram is an essential diagnostic diagram for stellar structure and evolution, which has now been in use for more than 100 years. Our spectroscopic Hertzsprung-Russell (sHR) diagram shows the inverse of the…
The absolute visual magnitude as function of the observed colour (B-V), also named Hertzsprung-Russell diagram can be described through five equations; that in presence of calibrated stars means eight constants. The developed framework…
Our understanding of large amplitude pulsating stars and their status in stellar evolution is briefly reviewed. The paper then describes the near-infrared light curves of various asymptotic giant branch stars, concentrating on possible…
Scientific research is a continuous process, and the speed of future progress can be estimated by the pace of finding explanations for previous research questions. In this observers based view of stellar pulsation and asteroseismology, we…
Helium-star models were dynamically evolved into the region of the HR Diagram where R CrB variables are found. The MESA stellar evolution code was able to pick up pulsational instabilities with cycle lengths that are compatible with the…
We analyse 829,481 stars from the Next Generation Transit Survey (NGTS) to extract variability periods. We utilise a generalisation of the autocorrelation function (the G-ACF), which applies to irregularly sampled time series data. We…
Astronomical data are typically irregular in time, e.g. the space (HIPPARCOS/TYCHO, KEPLER, GAIA, WISE etc.) and ground-based CCD (NSVS, ASAS, CRTS, SuperWASP etc.) and photographic (Harvard, Sonneberg, Odessa etc.) photometrical surveys.…
The aspects of the analysis of photometric time-series obtained on double-mode or multiperiodic pulsating stars are briefly reviewed. In particular, the ratios between frequencies are used to pin cases revealing peculiarities. In addition…
We infer the dynamical masses of stars across the Hertzsprung-Russell (H-R) diagram using wide binaries from the Gaia survey. Gaia's high-precision astrometry measures the wide binaries' orbital motion, which contains the mass information.…
The stellar evolution theory of massive stars remains uncalibrated with high-precision photometric observational data mainly due to a small number of luminous stars that are monitored from space. Automated all-sky surveys have revealed…
The Kepler spacecraft is providing photometric time series with micro-magnitude precision for thousands of variable stars. The continuous time-series of unprecedented time span open up opportunities to study the pulsational variability in…
This work is part of an effort to detect secular variable objects in large scale surveys by analysing their path in color-magnitude diagrams. To this aim, we first present the variability morphologies in the V/V-I diagram of several types…
In this study, the distances of stellar systems classified as cataclysmic variables in the literature were determined by using the distance compiled from Bailer-Jones et al. (2021). The spatial distributions of cataclysmic variables in the…
The spectroscopic and photometric analysis of sample Am stars are carried out to determine the stellar characteristics of each studied star. The CCD photometric analysis of HD 98851 and HD 207561 show clear evidence of pulsation variability…
Several decades of observations of the most massive and most luminous stars have revealed a complex upper HR Diagram, shaped by mass loss, and inhabited by a variety of evolved stars exhibiting the consequences of their mass loss histories.…
Stars exhibit a bewildering variety of rapidly variable behaviors ranging from explosive magnetic flares to stochastically changing accretion to periodic pulsations or rotation. The principal Rubin Observatory Legacy Survey of Space and…
Variability in the sky has been known for centuries, even millennia, but our knowledge of it is very incomplete even at the bright end. Current technology makes it possible to built small, robotic optical instruments, to record images and…
Time-resolved ground-based surveys in general, and photometric ones in particular, have played a crucial role in building up our knowledge of the properties, physical nature, and the very existence of the many different classes of variable…
We discuss in detail the pulsation properties of variable stars in globular clusters (GCs) and in Local Group (LG) dwarf galaxies. Data available in the literature strongly support the evidence that we still lack a complete census of…