Related papers: Solar twins in M67
Asteroseismology of stellar clusters is potentially a powerful tool. The assumption of a common age, distance, and chemical composition provides constraints on each cluster member, which significantly improves the asteroseismic output.…
Recent works have shown how the [C/N] ratio in stars after the first dredge-up (FDU) can be used as an age estimator in virtue of its dependence on stellar mass. For this purpose, precise predictions of the surface chemical composition…
Properties of solar twins reported by Lehmann et al. (2023) at kiloparsec distances from the local standard of rest (LSR) are compared to solar twins within 100 pc of the Sun. These have velocity distributions closely similar to those of…
A previous study of correlations between element abundance ratios, [X/Fe], and ages of solar twin stars is extended to include Sc, Mn, Cu, and Ba. HARPS spectra with S/N > 600 are used to derive very precise (+/- 0.01 dex) differential…
Star clusters are good tracers for formation and evolution of galaxies. We compared different fitting methods by using spectra (or by combining photometry) to determine the physical parameters. We choose a sample of 17 star clusters in M33,…
NGC 6067 is a young open cluster hosting the largest population of evolved stars among known Milky Way clusters in the 50-150 Ma age range. It thus represents the best laboratory in our Galaxy to constrain the evolutionary tracks of 5-7…
The visual binary system 16~Cyg~A+B consists of similar solar twins, but a planetary companion is detected only in B. An intensive spectroscopic differential analysis is carried out to the Sun, 16~Cyg~A, and 16~Cyg~B, with particular…
Based on over 3000 BV images of M4 collected in years 1995-2009 we obtain light curves of 22 variables, 10 of which are newly detected objects. We identify four detached eclipsing binaries and eight contact binaries. Accurate periods are…
A most desirable feature of a standard candle to estimate astronomical distances is robustness against changes in metallicity and age. It is argued that the radii of main sequence stars with spectral types from solar to A0 show predictable…
We combine archival images for the nearby galaxy M33 (Triangulum Galaxy) from the ultraviolet (UV) to the infrared (IR) to derive ages, masses, and extinctions for the young star cluster population, and compare our physical parameters with…
An intensive spectroscopic study was performed for three representative solar twins (HIP 56948, HIP 79672, and HIP 100963) as well as for the Sun (Moon; reference standard), with an intention of (1) quantitatively discussing the…
The physical processes driving chemical evolution in the Milky Way can be probed using the distribution of abundances in low-mass FGK type stars in space phase at different times. During their final stages of evolution stars experience…
Photospheric C, N, and O abundances of 118 solar-analog stars were determined by applying the synthetic-fitting analysis to their spectra in the blue or near-UV region comprising lines of CH, NH, and OH molecules, with an aim of clarifying…
Context: Studies based on high-precision abundance determinations revealed that chemical patterns of solar twins are characterised by the correlation between the differential abundances relative to the Sun and the condensation temperatures…
We study the stellar cluster population in M81, using the HST/ACS images in the filters F435W, F606W and F814W that cover a total field of view of approximately 140 square arcmin. We present details about the selection criteria, which were…
We present a study of the properties of the star-cluster systems around pseudo-bulges of late-type spiral galaxies using a sample of 11 galaxies with distances from 17 to 37 Mpc. Star clusters are identified from multiband HST ACS and WFPC2…
We analyze the non-standard mixing history of the solar twins HIP 55459, HIP 79672, HIP 56948, HIP 73815, and HIP 100963, to determine as precisely as possible their mass and age. We computed a grid of evolutionary models with non-standard…
Aims: The precise determination of the stellar effective temperature of solar type stars is of extreme importance for Astrophysics. We present an effective temperature calibration for FGK dwarf stars using line equivalent width ratios of…
We present integrated JHK_s 2MASS photometry and a compilation of integrated-light optical photoelectric measurements for 84 star clusters in the Magellanic Clouds. These clusters range in age from ~200 Myr to >10 Gyr, and have [Fe/H]…
We present a detailed study of two luminous super star clusters in the starburst galaxy M82. Spectra, covering 3250-8790 A at a resolution of 1.6 A, were obtained at the 4.2 m William Herschel Telescope (WHT) for cluster F and the highly…