相关论文: Are pre-main-sequence stars older than we thought?

We present a new method for the evaluation of the age and age-spread among pre-main-sequence (PMS) stars in star-forming regions in the Magellanic Clouds, accounting simultaneously for photometric errors, unresolved binarity, differential…

Stellar age estimates are often calculated by interpolating a star's properties in a grid of models. However, different model grids will give different ages for the same star. We used the open cluster M67 to compare four different model…

We provide a set of analytic fits to the radii of pre-mainsequence stars in the mass range 0.1 < M/Msun < 8.0. We incorporate the formulae in N-body cluster models for evolution from the beginning of pre-main sequence. In models with 1,000…

We here develop an improved way of using a rotating star as a clock, set it using the Sun, and demonstrate that it keeps time well. This technique, called gyrochronology, permits the derivation of ages for solar- and late-type main sequence…

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.…

Past estimates for the age of the Upper Sco Association are typically 11-13 Myr for intermediate-mass stars and 4-5 Myr for low-mass stars. In this study, we simulate populations of young stars to investigate whether this apparent…

(Abridged) Protostellar systems evolve from prestellar cores, through the deeply embedded stage and then disk-dominated stage, before they end up on the main sequence. Knowing how much time a system spends in each stage is crucial for…

Ages have been derived for 55 globular clusters (GCs) from overlays of isochrones onto the turnoff photometry, assuming distances based on fits of zero-age horizontal branch (ZAHB) models to the lower bound of the observed distributions of…

We present a novel statistical algorithm, Stellar Ages, which currently infers the age, metallicity, and extinction posterior distributions of stellar populations from their magnitudes. While this paper focuses on these parameters, the…

We present a critical assessment of commonly used pre-main-sequence isochrones by comparing their predictions to a set of well-calibrated colour-magnitude diagrams of the Pleiades in the wavelength range 0.4 to 2.5 microns. Our analysis…

In this contribution I will discuss fundamental stellar parameters as determined from young star clusters; specifically those with ages less than or approximately equal to that of the Pleiades. I will focus primarily on the use of stellar…

In previous papers of the series we used a combination of optical and near-infrared colours to derive constraints on the relative age structure in globular cluster systems. Here, we present the details, strength and limitations of our…

Context:Ages derived from the low mass stars still contracting onto the main sequence often differ from ages derived from the high mass ones that have already evolved away from it. Aims:We investigate the general claim of disagreement…

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'…

A major impediment to understanding star formation in massive star forming regions (MSFRs) is the absence of a reliable stellar chronometer to unravel their complex star formation histories. We present a new estimation of stellar ages using…

We present an analysis of the positions and ages of young star clusters in eight local galaxies to investigate the connection between the age difference and separation of cluster pairs. We find that star clusters do not form uniformly but…

We address the question of whether protoplanetary discs around low mass stars (e.g. M-dwarfs) may be longer lived than their solar-type counterparts. This question is particularly relevant to assess the planet-making potential of these…

The determination of age is a critical component in the study of a population of stellar clusters. In this letter we present a new absolute age indicator for young massive star clusters based on J-H colour. This novel method identifies…

Recent studies have shown that an extended main-sequence turn-off is a common feature among intermediate-age clusters (1--3 Gyr) in the Magellanic Clouds. Multiple-generation star formation and stellar rotation or interacting binaries have…

We use the Geneva Syclist isochrone models that include the effects of stellar rotation to investigate the role that rotation has on the resulting colour-magnitude diagram (CMD) of young and intermediate age clusters. We find that if a…