Related papers: Convective Penetration in Early-Type Stars
Our understanding of stellar structure and evolution coming from one-dimensional (1D) stellar models is limited by uncertainties related to multi-dimensional processes taking place in stellar interiors. 1D models, however, can now be tested…
The formation mechanism of massive stars remains one of the main open problems in astrophysics, in particular the relationship between the mass of the most massive stars, and that of the cores in which they form. Numerical simulations of…
Rotational velocity, lithium abundance, and the mass depth of the outer convective zone are key parameters in the study of the processes at work in the stellar interior, in particular when examining the poorly understood processes operating…
We present the Pre-Main-Sequence (PMS) evolutionary tracks of stars with 0.0065~5.0Ms. The models were evolved from the PMS stellar birthline to the onset of hydrogen burning in the core. The convective turnover timescales which enables an…
We find that convective regions of collapsing massive stellar cores possess sufficient stochastic angular momentum to form intermittent accretion disks around the newly born neutron star (NS) or black hole (BH), as required by the…
Stars do not simply pop up on the main sequence. Before the stars arrive on the zero-age main sequence, they form in the collapses of molecular clouds, gain matter through accretion processes, and compress their cores until hydrogen can…
Convective-core overshoot mixing is a significant uncertainty in stellar evolution. Because numerical simulations and turbulent convection models predict exponentially decreasing radial rms turbulent velocity, a popular treatment of the…
Many observational results seem to indicate more efficient mixing processes in intermediate mass stars (5-20 M$_{\odot}$) than the expected by the standard models. These processes are usually thought to be caused by stellar rotation. Our…
Asteroseismology gives us the opportunity to look inside stars and determine their internal properties. Based on these observations, estimations can be made for the amount of the convective boundary mixing and envelope mixing of such stars,…
Context: We study the impact of two-dimensional spherical shells on compressible convection. Realistic profiles for density and temperature from a one-dimensional stellar evolution code are used to produce a model of a large stellar…
We present a detailed analysis of the dynamics of proto-compact star (PCS) convection and the core ${}^2\!g_1$-mode in core-collapse supernovae based on general relativistic 2D and 3D neutrino hydrodynamics simulations. Based on 2D…
We present numerical investigations into the formation of massive stars from centrally condensed turbulent cores. The results of five hydrodynamical simulations are described, following the collapse of the core, fragmentation and the…
In stellar evolution calculations, the local pressure scale height is often used to empirically constrain the amount of convective core overshoot. However, this method brings unsatisfactory results for low-mass stars (< 1.1 -1.2 Mo for Z=…
Core overshoot is a large source of uncertainty in constructing stellar models. Whether the amount of overshoot is constant or mass dependent is not completely known, even though models sometimes assume a mass-based trend. In this work we…
We use I band imaging to perform a variability survey of the 13 Myr-old cluster h Per. We find a significant fraction of the cluster members to be variable. Most importantly, we find that variable members lie almost entirely on the…
Our understanding of the convective-engine paradigm driving core-collapse supernovae has been used for 2 decades to predict the remnant mass distribution from stellar collapse. These predictions improve as our understanding of this engine…
The mass distributions of dense cores in star-forming regions are measured to have a shape similar to the initial mass function of stars. This has been generally interpreted to mean that the constituent cores will form individual stars or…
(Abridged) We describe the results of three-dimensional (3D) numerical simulations designed to study turbulent convection in the stellar interiors, and compare them to stellar mixing-length theory (MLT). Simulations in 2D are significantly…
We constructed hydrodynamical model atmospheres for mid M-type main-, as well as pre-main-sequence objects. Despite the complex chemistry encountered in such cool atmospheres a reasonably accurate representation of the radiative transfer is…
The detection of mixed oscillation modes offers a unique insight into the internal structure of core helium burning (CHeB) stars. The stellar structure during CHeB is very uncertain because the growth of the convective core, and/or the…