相关论文: The evolutionary status of W Ursae Majoris-type sy…
CONTEXT: Accurate physical properties of eclipsing stars provide important constraints on models of stellar structure and evolution, especially when combined with spectroscopic information on their chemical composition. Empirical…
[Abridged] Context: Radiation-driven mass loss plays a key role in the life-cycles of massive stars. However, basic predictions of such mass loss still suffer from significant quantitative uncertainties. Aims: We develop new…
Mass loss is a key uncertainty in the evolution of massive stars. Stellar evolution calculations must employ parametric algorithms for mass loss, and usually only include stellar winds. We carry out a parameter study of the effects of wind…
Grids of models of massive stars ($M \ge$ 20 $M_\odot$) with rotation are computed for metallicities $Z$ ranging from that of the Small Magellanic Cloud (SMC) to that of the Galactic Centre. The hydrostatic effects of rotation, the…
We present the multi-band photometric and low-resolution spectroscopic analysis of four W Ursae Majoris eclipsing binaries (EWs) - J080510.1+141528 (hereinafter as J0805a), J080516.3+143138 (hereinafter as J0805b), J143358.7+053953…
W UMa type binaries have two defining characteristics. These are (i) the effective temperatures of both components are very similar, and (ii) the secondary (currently less massive) component is overluminous for its current mass. We consider…
The evolution of rotating stars with zero-age main sequence (ZAMS) masses in the range 8 to 25 M_sun is followed through all stages of stable evolution. The initial angular momentum is chosen such that the star's equatorial rotational…
The minimum mass ratio for tidal stability of a contact binary containing two unevolved main-sequence stars is calculated to be $\qmin\simeq0.09$ in the case of a mostly radiative primary, and is higher if an appreciable fraction of the…
Rotation has a number of important effects on the evolution of stars. It decreases the surface gravity, causes enhanced mass loss and leads to surface abundance anomalies of various chemical isotopes. We have adapted the Cambridge stellar…
With their emission-line dominated spectra, the appearance of Wolf-Rayet stars is shaped by their strong stellar winds. Yet, the physical mechanisms behind their high mass loss have long remained enigmatic. While we know nowadays that…
We perform three-dimensional numerical simulations of stellar winds of early-M dwarf stars. Our simulations incorporate observationally reconstructed large-scale surface magnetic maps, suggesting that the complexity of the magnetic field…
A large number of massive stars are known to rotate, resulting in significant distortion and variation in surface temperature from the pole to the equator. Radiatively driven mass loss is temperature dependent, so rapid rotation produces…
Some useful developments in the model physics are briefly presented, followed by model results on chemical enrichments and WR stars. We discuss the expected rotation velocities of WR stars. We emphasize that the (C+O)/He ratio is a better…
The interaction between weak magnetic fields and rotation can lead to instabilities that transport angular momentum (AM) and chemical elements affecting the evolution of massive stars. We explore the effects of the magneto-rotational…
M-dwarf stars are prime targets for exoplanet searches because of their close proximity and favorable properties for both planet detection and characterization. However, the potential habitability and atmospheric characterization of these…
We present evolutionary models of zero-metallicity very massive objects, with initial masses in the range 120 Msun -- 1000 Msun, covering their quiescent evolution up to central carbon ignition. In the attempt of exploring the possible…
Aims. We present a spectroscopic analysis of a sample of evolved stars in M67 (turn-off, subgiant and giant stars) in order to bring observational constraints to evolutionary models taking into account non-standard transport processes.…
We investigate the kinematics of the potential ultra-faint dwarf galaxy (UFD) UMa III/U1 using Bayesian inference to search for the signal of any potential intrinsic rotation. The magnitude of rotation is relevant to estimating the total…
The evolutionary scenario of early-type nitrogen-sequence Wolf-Rayet (WNE) stars predicts a slowly rotating subclass that typically forms after the red supergiant (RSG) phase. Their slow rotation rates are attributed to stellar winds that…
The understanding of the rotational evolution of early-type stars is deeply related to that of anisotropic mass and angular momentum loss. In this paper, we aim to clarify the rotational evolution of rapidly rotating early-type stars along…