相关论文: Mixing and Accretion in lambda Bootis Stars

Disk accretion to rotating stars with complex magnetic fields is investigated using full three-dimensional magnetohydrodynamic (MHD) simulations. The studied magnetic configurations include superpositions of misaligned dipole and quadrupole…

An investigation of the magnetospheric accretion and outflow signatures in sub-stellar objects is a natural extension of similar studies conducted on classical T Tauri stars (CTTS), and helps understand if brown dwarfs (BDs) follow the same…

Observations have revealed that most stars are born in clusters. As these clusters typically contain more mass in gas than in stars, accretion can play an important role in determining the final stellar masses. Numerical simulations of gas…

Double-line eclipsing binaries (DLEBs) have been recently used to constrain the amount of central mixing as a function of stellar mass, with contrasting results. In this work, we reanalyze the DLEB sample by Claret & Torres, using a…

Rotation has become an important element in evolutionary models of massive stars, specifically via the prediction of rotational mixing. Here, we study a sample of stars, including rapid rotators, to constrain such models and use nitrogen…

The understanding of transport processes inside the stars is one of the main goals of asteroseismology. Chemical turbulent mixing can affect the internal distribution of \mu near the energy generating core, having an effect on the…

This paper explores the mapping between the observable properties of a stellar halo in phase- and abundance-space and the parent galaxy's accretion history in terms of the characteristic epoch of accretion and mass and orbits of progenitor…

The role of accretion disks in the formation of low-mass stars has been well assessed by means of high angular resolution observations at various wavelengths. These findings confirm the prediction that conservation of angular momentum…

Simulations of the collapse and fragmentation of turbulent molecular clouds and dense young clusters show that encounters between disc-surrounded stars are relatively common events which should significantly influence the resulting disc…

Diffusion in cool B stars of the main sequence has been shown to strongly affect opacities and convection in cool B stars of the main sequence. We show here that diffusion in B stars maintains or enhances the excitation of pulsations in…

We have investigated an influence of the r-mode instability on hypercritically accreting ($\dot{M}\sim 1M_\odot {y}^{-1}$) neutron stars in close binary systems during their common envelope phases based on the scenario proposed by Bethe et…

Recent high-quality Hubble Space Telescope (HST) photometry shows that the main sequences (MS) stars of young star clusters form two discrete components in the color-magnitude diagram (CMD). Based on their distribution in the CMD, we show…

Low-mass stars exhibit, at all stages of their evolution, the signatures of complex physical processes that require challenging modeling beyond standard stellar theory. In this review, we recall the most striking observational evidences…

We present self-consistent calculations coupling numerical hydrodynamics simulations of collapsing pre-stellar cores and stellar evolution models of accreting objects. We analyse the main impact of consistent accretion history on the…

There is currently no accepted theoretical framework for the formation of the most massive stars, and the manner in which protostars continue to accrete and grow in mass beyond \sim10Msun is still a controversial topic. In this study we use…

Observations indicate that massive stars form in regions of very high surface density, ~1 g cm^-2. Clusters containing massive stars and globular clusters have a comparable column density. The total pressure in clouds of such a column…

Convective overshoot mixing is a critical ingredient of stellar structure models, but is treated in most cases by ad hoc extensions of the mixing-length theory for convection. Advanced theories which are both more physical and numerically…

As the number of planetary mass objects (PMOs, $\lessapprox$13 M$_{\rm{Jupiter}}$) at wider separation ($\gtrapprox$10 AU) grows, there is emerging evidence that they form differently from their higher-mass brown-dwarf (BD) counterparts.…

Fast Radio Bursts (FRBs) are intense, millisecond-duration radio transients that have recently been proposed to arise from coherent radiation mechanisms within the magnetosphere of neutron stars. Observations of repeating FRBs, including…

We study the star-disc interaction in the presence of the strong magnetic field ($B_\star=6.2kG$) of a slowly rotating star. This situation describes a post-merger of the spectral type B and has not been previously investigated. We perform…