We review and discuss horizontal branch (HB) stars in a broad astrophysical context,
including both variable and non-variable stars. A reassessment of the Oosterhoff dichotomy …

▪ Abstract Most of what we know about the stellar population of nearby, resolved galaxies
comes from the interpretation of their color-magnitude diagrams, by comparison with stellar …

We present a theoretical calibration of the RR Lyrae period-luminosity (PL) relation in the
UBVRIJHK Johnson-Cousins-Glass system. Our theoretical work is based on calculations of …

Context. The second parameter (the first being metallicity) defining the distribution of stars
on the horizontal branch (HB) of globular clusters (GCs) has long been one of the major …

This paper extends our previous study of planet/brown dwarf accretion by giant stars to solar-
mass stars located on the red giant branch. The model assumes that the planet is dissipated …

A" jump" in the blue horizontal-branch (HB) distribution in the (V, uy) color-magnitude
diagram has recently been detected in the globular cluster (GC) M13 (NGC 6205) by …

Enhancement and spread of helium among globular cluster stars have been recently
suggested as a way to explain the horizontal-branch blue tails in those clusters that show a …

I examine the influence of planets on the location of stars on the Hertzsprung-Russel
diagram as the stars turn to the horizontal branch. As stars that have planetary systems …

The majority of globular clusters show chemical inhomogeneities in the composition of their
stars, apparently due to a second stellar generation in which the forming gas is enriched by …

Extensive photometric studies of the globular clusters located toward the center of the Milky
Way have been historically neglected. The presence of patchy differential reddening in front …