相关论文: Metal Rich RR Lyrae Variables: I. The Evolutionary…

We have undertaken a search for variable stars in the metal-rich globular cluster NGC 6441 using time-series BV photometry. The total number of variables found near NGC 6441 has been increased to ~104, with 48 new variables being found in…

The results of a kinematic study of the Galactic bulge based on spectra of red giants in fields at projected distances of 1.4-1.8 kpc from the Galactic center are presented. There is a marked trend of kinematics with metallicity, in the…

We use the data of our extended catalog of spectroscopic determinations of elemental abundances in the atmospheres of Galactic-field RR Lyrae type variables to show that metal-rich RR Lyraes ($\rm{[Fe/H]} > -1.0$) have anomalous abundances…

We present predictions of the evolution of the light elements, Li, Be, and B, in the early epochs of the Galactic halo, using a model of supernova-induced chemical evolution based on contributions from supernovae (SNe) and cosmic rays…

(Abridged version) We present the first detailed imaging polarization observations of six SMC and six LMC clusters, known to have large populations of B-type stars which exhibit excess H-alpha emission, to constrain the evolutionary status…

A grid of synthetic horizontal-branch (SHB) models based on HB evolutionary tracks with improved physics has been constructed to reconsider the theoretical calibration of the dependence of M_v(RR) on metallicity in globular clusters, and…

We combine observed metallicity, optical and infrared magnitudes with evolutionary and pulsation models to derive average luminosities for 156 single-mode RR Lyrae stars. These luminosities are compared with those obtained from the Gaia…

The kinematics of 122 red giants and 124 RR Lyrae variables in the solar neighborhood is studied using accurate measurements of their proper motions by the Hipparcos astrometry satellite, combined with the published photometric distances,…

Stellar evolution theory predicts the existence of He-core remnants of the primary components of intermediate-mass close binaries that lost most of their H/He envelopes due to the mass exchange. They are expected to be observed as (1-7)…

The RR Lyrae instability strip (IS) in NGC 1851 is investigated, and a model is presented which reproduces the pulsational properties of the RR Lyrae population. In our model, a stellar component within the IS that displays minor helium…

RR Lyrae stars (RRLs) are tracers of the Milky Way's fossil record, holding valuable information on its formation and early evolution. Owing to the high interstellar extinction endemic to the Galactic plane, distant RRLs lying at low…

RR Lyrae stars being distance indicators and tracers of old population serve as excellent probes of the structure, formation, and evolution of our Galaxy. Thousands of them are being discovered in ongoing wide-field surveys. The OGLE…

We have used photometric data on almost 91 000 fundamental-mode RR Lyrae stars (type RRab) detected by the OGLE survey to investigate properties of old populations in the Milky Way. Based on their metallicity distributions, we demonstrate…

We present key sample results of a systematic survey of the pulsation properties of models of hot B subdwarfs. We use equilibrium structures taken from detailed evolutionary sequences of solar metallicity (Z = 0.02) supplemented by grids of…

We present models of the late stages of stellar evolution intended to explain the UV upturn phenomenon in elliptical galaxies. Such models are sensitive to values of a number of poorly-constrained physical parameters, including metallicity,…

Here we present the detailed analysis of some modulated Kepler and K2 RR Lyrae stars that show peculiar bump progression in respect to the pulsation phase.

We use our synthetic Horizontal Branch (HB) procedure to approach the debated problem concerning the adequacy of canonical HB stellar models to account for the observed peaked distribution of RR Lyrae fundamentalised periods in the globular…

We present B, V, R, and H alpha photometry of 8 clusters in the Small Magellanic Cloud, 5 in the Large Magellanic Cloud, and 3 Galactic clusters, and use 2 color diagrams (2-CDs) to identify candidate Be star populations in these clusters.…

We estimate the empirical R parameter in 26 Galactic Globular Clusters covering a wide metallicity range, imaged by WFPC2 on board the HST. The improved spatial resolution permits a large fraction of the evolved stars to be measured and…

It is an observational fact that bulges of spiral galaxies contain a high fraction of old and metal-rich stars. Following this observational fact, we have investigated colors of 21 bulges hosted by a selected sample of high surface…