Related papers: RR Lyrae Pulsation Theory
RR Lyrae stars in the Milky Way are good tracers to study the kinematic behaviour and spatial distribution of older stellar populations. A recently established well documented sample of 217 RR Lyr stars with V<12.5 mag, has been used to…
The period of pulsation and the structure of the light curve for Cepheid and RR Lyrae variables depend on the fundamental parameters of the star: mass, radius, luminosity, and effective temperature. Here we train artificial neural networks…
Pulsars are unique astrophysical laboratories because of their clock-like timing precision, providing new ways to test general relativity and detect gravitational waves. One impediment to high-precision pulsar timing experiments is timing…
The outskirts of the Milky Way disc have been known to be warped since the late 1950s. Although various stellar populations have shown an underlying warped distribution, the relation between the age of the population and the warp they trace…
RR Lyrae stars have long been considered unequivocal tracers of old (>10 Gyr) and metal-poor ($\mathrm{[Fe/H]}<-0.5$) stellar populations. First, because these populations are where they are readily found and because, according to canonical…
RR Lyrae are a well-known class of pulsating horizontal branch stars widely used as tracers of old, metal-poor stellar populations. However, mounting observational evidence shows that a significant fraction of these stars may be young and…
This paper summarizes the main results of our recent study of the non-Blazhko RR Lyrae stars observed with the Kepler space telescope. These stars offer the opportunity for studying the stability of the pulsations of RR Lyrae stars and for…
We collected over 6000 high-resolution spectra of four dozen field RR Lyrae (RRL) variables pulsating either in the fundamental (39 RRab) or in the first overtone (9 RRc) mode. We measured radial velocities (RVs) of four strong metallic and…
With the help of linear pulsation models we briefly discuss the peculiar period ratios characteristic for modulated double-mode RR Lyrae stars.
Using the novel data set of the MACHO project, we show that three ``Blazhko Effect'' RR Lyrae stars show nearly-pure amplitude modulation of a single pulsation mode. This is strong observational evidence that the ``Oblique Pulsator Model''…
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…
The Blazhko effect is a long term, generally irregular modulation of the light curves that occurs in a sizeable number of RR Lyrae stars. The physical origin of the effect has been a puzzle ever since its discovery over a hundred years ago.…
The properties of RR Lyrae variables make them excellent probes of the formation and evolution of a stellar population. The mere presence of such stars necessitates an age greater than ~10 Gyr while their periods and amplitudes can be used…
Massive stars play a major role not only in stellar evolution but also galactic evolution theory. This is because of their dynamical interaction with binary companions, and because their strong winds and explosive deaths as supernovae…
Machine learning has achieved an important role in the automatic classification of variable stars, and several classifiers have been proposed over the last decade. These classifiers have achieved impressive performance in several…
The luminosities and effective temperatures, as well as the whole bolometric lightcurves of nonlinear convective RR Lyrae models with 0.0001<Z<0.006 are transformed into the SDSS photometric system. The obtained ugriz lightcurves, mean…
We introduce a model for pulsars in which non-radial oscillations of high spherical degree (l) aligned to the magnetic axis of a spinning neutron star reproduce the morphological features of pulsar beams. In our model, rotation of the…
Since the first detection of intracluster planetary nebulae in 1996, imaging and spectroscopic surveys identified such stars to trace the radial extent and the kinematics of diffuse light in clusters. This topic of research is tightly…
Asteroseismology has become an indispensable method for measuring stellar ages and radii, while binary systems remain the most prevalent tool for determining stellar masses. The synergy of the two, namely pulsating stars in binary systems,…
Long-period variables are bright, evolved red giant stars showing periodic photometric changes due to stellar pulsation. They follow one or more period-luminosity and period-age relations, which make them highly promising distance…