Related papers: Characteristics of solar-like oscillations of seco…
Using a stellar population-synthesis method, we studied the distributions of {\nu}_max and {\Delta}{\nu} of simulated clusters with various ages and metallicities. Except for the confirmed peak (RC peak) of {\Delta}{\nu} of red-clump (RC)…
The distributions of the frequencies of the maximum oscillation Power ({\nu}_max) and the large frequency separation ( {\Delta}{\nu}) of red giant stars observed by CoRoT have a dominant peak. Miglio et al. (2009) identified that the stars…
The investigation of global, resonant oscillation modes in red giant stars offers valuable insights into their internal structures. In this study, we investigate in detail the information we can recover on the structural properties of…
Modeling of the stars in the red clump (RC) is challenging, due to the uncertainties associated with the physical processes happening in their core and during the helium flash. By probing the internal stellar structure, asteroseismology…
On the basis of a recently derived color-metallicity relation and stellar parameters from the Sloan Digtal Sky Survey Data Release 7 spectroscopic survey, a large sample of red horizontal branch candidates have been selected to serve as…
The large frequency separation between modes of the same degree and consecutive orders in a star is approximately proportional to the square root of its mean density. To determine the large frequency separation as accurately as possible a…
Uncertainties on central mixing in main sequence (MS) and core He-burning (He-B) phases affect key predictions of stellar evolution such as late evolutionary phases, chemical enrichment, ages etc. We propose a test of the extension of…
Oscillation modes of a mixed character are able to probe the inner region of evolved low-mass stars and offer access to a range of information, in particular, the mean core rotation. Ensemble asteroseismology observations are then able to…
We study prospects for seismic sounding the layer of a partial mixing above the convective core in main-sequence stars with masses in the 1.2 -- 1.9 solar mass range. There is an initial tendency to an increase of convective core mass in…
Red clump stars still pose open questions regarding several physical processes, such as the mixing around the core, or the nuclear reactions, which are ill-constrained by theory and experiments. The oscillations of red clump stars, which…
We describe a method for the determination of stellar [C/Fe] abundance ratios using low-resolution (R = 2000) stellar spectra from the SDSS and SEGUE. By means of a star-by-star comparison with a set of SDSS/SEGUE spectra with available…
The secondary-to-primary B/C ratio is widely used to study the cosmic ray (CR) propagation processes in the Galaxy. It is usually assumed that secondary nuclei such as Li-Be-B are entirely generated by collisions of heavier CR nuclei with…
Asteroseismology can provide joint constraints on masses and radii of individual stars. While this approach has been extensively tested for red giant branch (RGB) stars, it has been more difficult to test for helium core-burning red-clump…
We investigate the predicted Color-Magnitude distribution of metal-rich Horizontal Branch (HB) stars, discussing selected theoretical models computed under various assumptions about the star metallicity and the efficiency of super-adiabatic…
We present a detailed analysis of the radial distribution of light-element multiple populations (LE-MPs) in the massive and dense globular cluster M80 based on the combination of UV and optical Hubble Space Telescope data. Surprisingly, we…
Abundances of R Coronae Borealis stars (RCBs) and Extreme Helium stars (EHes) are discussed. Recent estimates of the $s$-process elements in hot extreme helium stars show enhancements of lighter $s$-process elements (Y, Zr) relative to…
The red clump stars in the open cluster NGC 752 present a peculiar distribution in the colour-magnitude diagran (CMD): the clump is observed to present a faint extension, slightly to the blue of the main concentration of clump stars. We…
RCB stars are $L\approx10^4\,L_{\odot}$ solar-mass objects that can exhibit large periods of extinction from dust ejection episodes. Many exhibit semiregular pulsations in the range of $30-50$ days with semi-amplitudes of $0.05-0.3$…
Even though it is broadly accepted that single Be stars are rapidly rotating stars surrounded by a flat rotating circumstellar disk, there is still a debate about how fast these stars rotate and also about the mechanisms involved in the…
The temperature distribution of field Li-rich red giants suggests the presence of a population of Li-rich red clump (RC) stars. One proposed explanation for this population is that all stars with masses near 2 $M_\odot$ experience a…