99 datasets found

A complete sample of blue horizontal branch (BHB) stars in the magnitude range 13.0<V<16.5 is isolated in two Galactic fields that have previously been searched for RR...

Observational evidence has accumulated in recent years, showing that the Galactic bulge includes two populations, a metal-poor one and a metal-rich one, which in addition to...

Stars that are found on the blue horizontal-branch (BHB) evolved from low-mass stars that have completed their core hydrogen-burning main sequence (MS) stage and undergone the...

By using a large sample of fundamental mode RR Lyrae stars with published spectroscopic iron abundances and gravities, we point out the importance of correcting these abundances...

In this work, we characterize the properties of HB stars in the GCs {omega} Cen and NGC 6752. We use dedicated model atmospheres and synthetic spectra grids computed using a...

Lithium and the carbon isotope ratio ^12^C/^13^C can change during the red giant branch as a result of extra-mixing. This is associated usually with thermohaline mixing acting...

Blue horizontal-branch stars evolve from low-mass stars that have completed their main-sequence lifetimes and undergone a helium flash at the end of their red-giant phase. As...

The presence of extreme horizontal branch (EHB) and blue hook stars in some Galactic globular clusters (GGCs) constitutes one of the remaining mysteries of stellar evolution....

Homogeneous investigations of red giant stars in open clusters contribute to studies of internal evolutionary mixing processes inside stars, which are reflected in abundances of...

Libraries of stellar spectra find many uses in astrophysics, from photometric calibration to stellar population synthesis. We present low resolution spectra of 40 stars from 0.2...

V391 Peg (alias HS 2201+2610) is a subdwarf B (sdB) pulsating star that shows both p- and g-modes. By studying the arrival times of the p-mode maxima and minima through the O-C...

Recent statistical studies prove that the percentage of RR Lyrae pulsators that are located in binaries or multiple stellar systems is considerably lower than might be expected....

We present the results of an extensive survey for rapid pulsators among Extreme Horizontal Branch (EHB) stars in {omega} Cen. The observations performed consist of nearly 100...

We used FLAMES+GIRAFFE (Medusa mode) at the VLT to obtain moderately high resolution spectra for 30 red horizontal branch (RHB) stars, 4 RR Lyrae variables, and 17 blue...

NGC 288 is a globular cluster with a well-developed blue horizontal branch covering the u-jump that indicates the onset of diffusion. It is therefore well suited to study the...

We obtained high-resolution spectra for 94 candidate stars belonging to the HB of M 22 with FLAMES. Previous works have indicated that this cluster has split subgiant (SGB) and...

High-velocity halo stars provide important information about the properties of the extreme Galactic halo. The study of Population II unbound and bound stars enables us better...

To check the impact of the multiple population scenario for globular clusters on their horizontal branch (HB), we present an analysis of the composition of 110 red HB (RHB)...

The chemical composition of horizontal branch (HB) stars might help to clarify the formation history of individual globular clusters (GCs). We studied the Na-O anti-correlation...

Globular clusters have been recognized to host multiple stellar populations. A spectacular example of this is the massive cluster NGC 2808, where multiple populations have been...