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

Our ability to determine stellar ages from measurements of stellar rotation, hinges on how well we can measure the dependence of rotation on age for stars of different masses. Rotation periods for stars in open clusters are essential to…

We perform a systematic reanalysis of the age distribution of Galactic open star clusters. Using a catalogue of homogeneously determined ages for 834 open clusters contained in a 2 kpc cylinder around the Sun and characterised with…

Major photometric monitoring campaigns of star-forming regions in the past decade have provided rich rotation period distributions of pre-main-sequence stars. The rotation periods span more than an order of magnitude in period, with most…

Recent studies have shown that the observed main-sequence turn-off (MSTO) in colour-magnitude diagrams of intermediate age (1-2 Gyr) clusters in the LMC are broader than would be nominally expected for a simple stellar population. This has…

Observations of pre-/proto-stellar cores in young star-forming regions show them to be mass segregated, i.e. the most massive cores are centrally concentrated, whereas pre-main sequence stars in the same star-forming regions (and older…

We apply for the first time a two-dimensional fitting statistic, $\tau^2$, to rotational evolution models (REMs) of stars (0.1 to 1.3 $M_{\odot}$) on the period-mass plane. The $\tau^2$ statistic simultaneously considers all cluster…

We present estimates of stellar age and mass for 0.93 million Galactic disk main sequence turn-off and sub-giant stars from the LAMOST Galactic Spectroscopic Surveys. The ages and masses are determined by matching with stellar isochrones…

Gyrochronology enables the derivation of ages of late-type main sequence stars based on their rotation periods and a mass proxy, such as color. It has been explored in open clusters, but a connection to field stars has yet to be…

The comparison of visual magnitudes of stars compiled in old catalogues is expected to yield information about their long-term magnitude variations. In seven old catalogues whose historical data have been intensively compared, 2123 sampled…

The post-starburst region B in M82 and its massive star cluster component have been the focus of multiple studies, with reports that there is a large population of coeval clusters of age ~1 Gyr, which were created with a Gaussian initial…

It is often argued that young stellar clusters suffer a significant infant mortality that is partly related to the expulsion of dust and gas in their early phases caused by radiation pressure from hot stars and supernovae. Near-infrared…

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…

The recent Gaia Data Release 1 of stellar parallaxes provides ample opportunity to find metal-poor main-sequence stars with precise parallaxes. We select 21 such stars with parallax uncertainties better than $\sigma_\pi/\pi\leq0.10$ and…

We present a new study of the spatial distribution and ages of the star clusters in the Small Magellanic Cloud (SMC). To detect and estimate the ages of the star clusters we rely on the new fully-automated method developed by Bitsakis et…

We present broad-band (U, V, I,and H) and narrow-band(H-alpha+[N II] and Paschen-alpha) images of the circumnuclear starburst rings in two nearby spiral galaxies, NGC 1512 and NGC 5248, obtained with WFPC2 and NICMOS on HST. Combined with…

The origin of extended main-sequence turn-offs (eMSTO) in star clusters younger than 2 Gyr still challenges our current understanding of stellar evolution. Exploiting data from Gaia Data Release 3 (DR3), we investigate eMSTOs in a large…

In the Large Magellanic Cloud (LMC), there have been very few clusters observed with ages between 4 and 11 Gyr. This phenomenon is sometimes referred to as the `LMC age gap'. We constructed a model of the cluster age distribution aimed at…

We perform calculations of pre-main sequence evolution of stars from 1 to $85 M_{\odot}$ with growing accretion rates $\dot{M}$. The values of $\dot{M}$ are taken equal to a constant fraction $\tilde{f}$ of the rates of the mass outflows…

In this paper, we present photometry for young star clusters in M31, which are selected from Caldwell et al. These star clusters have been observed as part of the Beijing--Arizona--Taiwan--Connecticut (BATC) Multicolor Sky Survey from 1995…

Globular star clusters that formed at the same cosmic time may have evolved rather differently from a dynamical point of view (because that evolution depends on the internal environment) through a variety of processes that tend…