Related papers: The coronal evolution of pre-main-sequence stars

Stars spend most of their lifetime on the main sequence (MS), where hydrogen burning establishes the internal chemical structure that governs the subsequent evolution. In massive stars, mass loss through winds and binary interactions can…

We present a statistical analysis of simultaneous optical and X-ray light curves, spanning 600 ks, for 814 pre-main-sequence (PMS) stars in the Orion Nebula Cluster. The aim of this study is to establish the relationship, if any, between…

The nature of the mechanisms apparently driving X-rays from intermediate mass stars lacking strong convection zones or massive winds remains poorly understood, and the possible role of hidden, lower mass close companions is still unclear. A…

We compute and analyze the evolution of primordial stars of masses at the ZAMS between 5 M_sun and 10 M_sun, with and without overshooting. Our main goals are to determine the nature of the remnants of massive intermediate-mass primordial…

We have modelled the X-ray emission of T Tauri stars assuming that they have isothermal, magnetically-confined coronae. These coronae extend outwards until either the pressure of the hot coronal gas overcomes the magnetic field, or, if the…

The effect of atomic diffusion on the Main Sequence (MS) of metal-poor low mass stars is investigated. Since diffusion alters the stellar surface chemical abundances with respect to their initial values, one must ensure - by calibrating the…

Mass loss due to line-driven winds is central to our understanding of the evolution of massive stars. We extend the evolution models introduced in Paper I, where the mass loss recipe is based on the simultaneous calculation of the wind…

Observations of the Ly-alpha forest at z~3 reveal an average metallicity Z~0.01 Z_solar. The high-redshift supernovae that polluted the IGM also accelerated relativistic electrons. Since the energy density of the CMB scales as (1+z)^4, at…

We present an analytical study of a large sample of ~109 young stellar objects in the X-ray. Our objects were detected in X-ray independent of age. Unexpectedly, the X-ray energy is somewhat correlated with the ages. It decreases with time…

Young stars on their way to the ZAMS evolve in significantly different ways depending on mass. While the theoretical and observational properties of low- and intermediate-mass stars are rather well understood and/or empirically tested, the…

We show that non-magnetic models for the evolution of pre-main-sequence (PMS) stars *cannot* simultaneously describe the colour-magnitude diagram (CMD) and the pattern of lithium depletion seen in the cluster of young, low-mass stars…

Improving our understanding of the initial conditions and earliest stages of star formation is crucial to gain insight into the origin of stellar masses, multiple systems, and protoplanetary disks. We review the properties of low-mass dense…

Solar-like stars (M < 1.3 Msun) lose angular momentum through their magnetized winds. The resulting evolution of the surface rotation period, which can be directly measured photometrically, has the potential to provide an accurate indicator…

We highlight differences in spectral types and intrinsic colors observed in pre-main sequence (pre-MS) stars. Spectral types of pre-MS stars are wavelength-dependent, with near-infrared spectra being 3-5 spectral sub-classes later than the…

The evidence for a shortage of exosolar planets with semimajor axes -1.1 <= log (a/AU) <= -0.2 is investigated. It is shown that this valley results from a gap in the radial distribution of planets, orbiting stars with masses M >= 1.2…

We report the detection of hard X-ray emission (>2 keV) from a number of point sources associated with the very young massive star-forming region IRAS 19410+2336. The X-ray emission is detected from several sources located around the…

Stellar coronae are believed to be the main birthplace of various stellar magnetic activities. However, the structures and properties of stellar coronae remain poorly understood. Using the Space Weather Modelling Framework with the…

Some physical processes that occur during a star's main-sequence evolution also affect its post main-sequence evolution. It is well known that stars with masses above approximately 1.1 $M_{\odot}$ have well-mixed convective cores on the…

Context. Precise determination of stellar masses is necessary to test the validity of pre-main-sequence (PMS) stellar evolutionary models, whose predictions are in disagreement with measurements for masses below 1.2 Msun. To improve such a…

We have re-analyzed using a hydrodynamic model large flaring events on three different categories of pre-main sequence (PMS) stars: the young stellar object (YSO) YLW 15, the classical T Tauri star (CTTS) LkHalpha92, the weak-line T Tauri…