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Pulsation period changes as a tool to identify pre-zero age horizontal branch stars
(2010)
One of the most dramatic events in the life of a low-mass star is the He flash, which takes place at the tip of the red giant branch (RGB) and is followed by a series of secondary flashes before the star settles into the ...
Humps and bumps: the effects of shocks on the optical light curves of fundamental-mode RR Lyrae stars
(EDP SCIENCES S A, 2020)
We present the most extended and homogeneous study carried out so far of the main and early shocks in 1485 RR Lyrae stars in the Galactic bulge observed by the Optical Gravitational Lensing Experiment. We selected nonmodulated ...
Chronography of the Milky Way's Halo System with Field Blue Horizontal-branch Stars
(Iop Publishing, 2015-11-01)
In a pioneering effort, Preston et al. reported that the colors of bluehorizontal-branch (BHB) stars in the halo of the Galaxy shift withdistance, from regions near the Galactic center to about 12 kpc away,and interpreted ...
The variable stars in the field of NGC 6139: a critical approach to their reddening and membership
(Oxford University Press, 2023-09-01)
We present a CCD VI time-series analysis of the globular cluster NGC 6139 and its variable star population. Using the astrometric data available in Gaia-DR3, we performed a membership analysis that enabled the construction ...
ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
(De Gruyter Open Ltd, 2017-04)
The ε mechanism is a self-excitation mechanism of stellar pulsations which acts in regions where nuclear burning takes place. It has been shown that the ε mechanism can excite pulsations in hot pre-horizontal branch stars ...
G2C2-IV.A novel approach to study the radial distributions of multiple populations in Galactic globular clusters
(OXFORD UNIV PRESS, 2015)
We use the horizontal branch (HB) morphology of 48 Galactic globular clusters (GCs) to study the radial distributions of the different stellar populations known to exist in GCs. Assuming that the (extremely) blue HB stars ...
First stars XIII. Two extremely metal-poor RR Lyrae stars
(EDP SCIENCES S A, 2011)
Context. The chemical composition of extremely metal-poor stars (EMP stars; [Fe/H] < similar to -3) is a unique tracer of early nucleosynthesis in the Galaxy. As such stars are rare, we wish to find classes of luminous ...
SEMI-EMPIRICAL DETERMINATION OF THE MASS DISTRIBUTION OF HORIZONTAL BRANCH STARS IN M3
(AMERICAN INSTITUTE OF PHYSICS, 2007)
We determine, by means of a semi-empirical study, the masses of horizontal branch stars in the globular cluster M3 (NGC 5272). We used the most recent and reliable observational datasets (broadband BVI photometry) available ...
Helium enhancement among horizontal-branch stars and the near-UV color-magnitude diagrams
(2015)
The distribution of horizontal branch stars in globular cluster color-magnitude diagrams is a sensitive probe of their original helium abundances. In this sense, they have been extensively used recently as indicators of ...