相关论文: Isochrones of M67 with an Expanded Set of Paramete…
The Gaia mission has provided highly accurate observations that have significantly reduced the scatter in the colour-magnitude diagrams of open clusters. As a result of the improved isochrone sequence of the open cluster M67, we have…
We present new evolutionary stellar models suitable for old Population I clusters, discussing both the consequences of the most recent improvements in the input physics and the effect of element diffusion within the stellar structures.…
Canonical grids of stellar evolutionary sequences have been computed for the helium mass-fraction abundances $Y = 0.25$, $0.29$, and $0.33$, and for iron abundances that vary from $-2.4$ to $+0.4$ (in 0.2 dex increments) when [$\alpha$/Fe]…
We determine the age and mass of the three best solar twin candidates in open cluster M67 through lithium evolutionary models. We computed a grid of evolutionary models with non-standard mixing at metallicity [Fe/H] = 0.01 with the…
An extensive grid of metal-rich isochrones utilizing the latest available input physics has been calculated for comparison with the old, metal-rich open cluster NGC 6791. The isochrones have been simultaneously fit to BV and VI color…
We have constructed a new set of isochrones, called the Y^2 Isochrones, that represent an update of the Revised Yale Isochrones (RYI), using improved opacities and equations of state. Helium diffusion and convective core overshoot have also…
A new grid of theoretical isochrones based on the Yale stellar evolution code using the OPAL and Kurucz opacities has been constructed. The grid of isochrones spans a wide range of metallicities, helium abundances and masses. The…
The mass at which a transition is made between stars that have radiative or convective cores throughout the core H-burning phase is a fairly sensitive function of Z (particularly the CNO abundances). As a consequence, the ~4 Gyr, open…
The rich open cluster M67 is known to have a chemical composition close to solar, and an age around 4Gyr. It thus offers the opportunity to check our understanding of the physics and the evolution of solar-type stars in a cluster…
We present a new set of isochrones in which the effect of the alpha-element enhancement is fully incorporated. These isochrones are an extension of the already published set of YY Isochrones (Yi et al. 2001: Paper 1), constructed for the…
As part of an ongoing program to measure detailed chemical abundances in nearby galaxies, we use a sample of young to intermediate age clusters in the Large Magellanic Cloud with ages of 10 Myr to 2 Gyr to evaluate the effect of isochrone…
We have calibrated an extensive set of BVI observations of M67. We have selected stars that are most likely to be single-star members of the cluster using proper motion, radial velocity, and variability information from the literature, and…
Context. The benchmark open cluster M67 is known to have solar metallicity and similar age as the Sun. It thus provides us a great opportunity to study the properties of solar twins, as well as the evolution of Sun-like stars. Aims.…
Evolutionary models taking into account radiative accelerations, thermal diffusion, and gravitational settling for 28 elements, including all those contributing to OPAL stellar opacities, have been calculated for solar metallicity stars of…
We present new isochrone fits to colour-magnitude diagrams of the Galactic globular cluster NGC\,6205 (M13). We utilise 34 photometric bands from the ultraviolet to mid-infrared by use of data from the {\it HST}, {\it Gaia} DR2, SDSS,…
The open cluster M67 has solar metallicity and an age of about 4Gyr. The turn-off mass is close to the minimum mass for which solar metallicity stars develop a convective core during main sequence evolution as a result of the development of…
We fit the upper main sequence of the Praesepe and Hyades open clusters using stellar models with and without rotation. When neglecting rotation, we find that no single isochrone can fit the entire upper main sequence at the clusters'…
Precision CCD uvbyCaHbeta photometry is presented of the old cluster, M67, covering one square degree with typical internal precision at the 0.005-0.020 mag level to V~17. The photometry is calibrated using standards over a wide range in…
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…
We present new isochrone fits to colour-magnitude diagrams of the Galactic globular cluster NGC 5904 (M5). We utilise 29 photometric bands from the ultraviolet to mid-infrared by use of the data from the {\it Hubble Space Telescope}, {\it…