相关论文: Stellar Envelope Convection calibrated by Radiatio…

Based on a new large, homogeneous photometric database of 35 Galactic globular clusters (GGCs), a set of distance and reddening independent relative age indicators has been measured. The observed D(V-I)_2.5 and D(V)(HB-TO) vs. metallicity…

The apparent age and mass of a stellar cluster can be strongly affected by stochastic sampling of the stellar initial mass function, when inferred from the integrated color of low mass clusters (less than ~10^4 solar masses). We use…

The ages of star clusters and co-moving stellar groups contain essential information about the Milky Way. Their special properties make them excellent tracers of galactic structure and key components to unlocking its star formation history.…

A variation of Newton's constant $G$ over cosmological time scales would modify the main-squence time of globular cluster (GC) stars. We have calculated the evolution of low-mass stars typical for GCs both for standard non-varying $G$ and…

Collisions of main sequence stars occur frequently in dense star clusters. In open and globular clusters, these collisions produce merger remnants that may be observed as blue stragglers. Detailed theoretical models of this process require…

Globular clusters formed in galactic mergers (e.g., The Antennae) can now be studied at different stages of their evolution. In young merger remnants (e.g., NGC 7252) these "second-generation" globulars appear by the hundreds as young halo…

Among the available methods for dating stars, gyrochronology is a powerful one because it requires knowledge of only the star's mass and rotation period. Gyrochronology relations have previously been calibrated using young clusters, with…

We aim to test the power of theoretical calibrations based on a new generation of MARCS models by comparisons with observational photomteric data. We calculate synthetic uvby-Hbeta colour indices from synthetic spectra. A sample of 388…

We present the result of our investigation on the impact of the low Solar abundance of Asplund and collaborators (2004) on the derived ages for the oldest star clusters based on isochrone fittings. We have constructed new stellar models and…

Determining stellar ages is challenging, as it depends on other stellar parameters in a non-linear way and often relies on stellar evolution models to infer the underlying relation between these parameters and age. This complexity increases…

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…

Detailed modelling of stellar oscillations is able to give precise estimates for stellar ages, but the inferred results typically depend on the adopted model parameters used for the age inference. High-quality asteroseismic data with…

Globular clusters can form inside their host galaxies at high redshift when gas densities were higher and gas-rich mergers were common. They can also form inside lower-mass galaxies that have since been accreted and tidally disrupted,…

Main sequence turnoff ages in young open clusters are complicated by turnoffs that are sparse, have high binarity fractions, can be affected by differential reddening, and typically include a number of peculiar stars. Furthermore, stellar…

When determining absolute ages of identifiably young stellar populations, results strongly depend on which stars are studied. Cooler (K, M) stars typically yield ages that are systematically younger than warmer (A, F, G) stars by a factor…

We investigate the relation between 1D atmosphere models that rely on the mixing length theory and models based on full 3D radiative hydrodynamic (RHD) calculations to describe convection in the envelopes of late-type stars. The adiabatic…

State-of-the-art one-dimensional (1D) stellar evolution codes rely on simplifying assumptions, such as mixing length theory, in order to describe superadiabatic convection. As a result, 1D stellar structure models do not correctly recover…

We investigate in detail the white dwarf cooling sequence of the globular cluster Messier 4. In particular we study the influence of various systematic uncertainties, both observational and theoretical, on the determination of the cluster…

In this study, we extend the dust-independent Hatzidimitriou (1991) relation between cluster age and $d_{B-R}$ color difference between the red giant branch (RGB) and red clump to younger cluster ages. We perform membership analysis on…

Modern hydrodynamic simulations of galaxy formation are able to predict accurately the rates and locations of the assembly of giant molecular clouds in early galaxies. These clouds could host star clusters with the masses and sizes of real…