相关论文: A novel analytic atmospheric $T(\tau)$ relation fo…
Relations between temperature, T, and optical depth, tau, are often used for describing the photospheric transition from optically thick to optically thin in stellar structure models. We show that this is well justified, but also that…
(abridged) The calculation of the thermal stratification in the superadiabatic layers of stellar models with convective envelopes is a long standing problem of stellar astrophysics, and has a major impact on predicted observational…
Based on detailed 2D numerical radiation hydrodynamics (RHD) calculations of time-dependent compressible convection, we have studied the dynamics and thermal structure of the convective surface layers of solar-type stars. The RHD models…
Mixing length theory is the predominant treatment of convection in stellar models today. Usually described by a single free parameter, alpha, the common practice is to calibrate it using the properties of the Sun, and apply it to all other…
Using the technique of Pade Approximants for the correlation contributions of charged particles we are able to reproduce complex mathematical expressions by simple algebraic formulas. The Pade formulas are analytical expressions, which…
The thermal properties of hydrodynamical simulations of galaxy clusters are usually compared to observations by relying on the emission-weighted temperature T_ew, instead of on the spectroscopic X-ray temperature T_spec, which is obtained…
We have observed a large sample of compact planetary nebulae in the near-infrared to determine how the 2^1P-2^1S HeI line at 2.058um varies as a function of stellar effective temperature, Teff. The ratio of this line with HI Br g at 2.166um…
One of the largest sources of uncertainty in stellar models is caused by the treatment of convection in stellar envelopes. One dimensional stellar models often make use of the mixing length or equivalent approximations to describe…
Predicting the merger timescale ($\tau_{\rm merge}$) of merging dark matter halos, based on their orbital parameters and the structural properties of their hosts, is a fundamental problem in gravitational dynamics that has important…
Stellar models have been computed for stars having [Fe/H] = 0.0 and -2.0 to determine the effects of using boundary conditions derived from the latest MARCS model atmospheres. The latter were fitted to the interior models at both the…
The temperatures and colors of stellar models are much less secure than predicted luminosities; consequently, it is important to ensure that the models which are used to interpret data for stellar populations satisfy existing observational…
Empirical correlations between stellar parameters such as rotation or radius and magnetic activity diagnostics require estimates of the effective temperatures and the stellar radii. The aim of this study is to propose simple methods that…
We establish a quantitative relationship between photometric and spectroscopic detections of solar-like oscillations using ab initio, three-dimensional (3D), hydrodynamical numerical simulations of stellar atmospheres. We present a…
A detailed spectroscopic study of the ISO-SWS data of the red giant Alpha Tau is presented, which enables not only the accurate determination of the stellar parameters of Alpha Tau, but also serves as a critical review of the ISO-SWS…
The recent discovery and characterization of the diversity of the atmospheres of exoplanets and brown dwarfs calls for the development of fast and accurate analytical models. We quantify the accuracy of the analytical solution derived in…
We introduce and test a new and highly efficient method for treating the thermal and radiative effects influencing the energy equation in SPH simulations of star formation. The method uses the density, temperature and gravitational…
We perform a calibration of the mixing length of convection in stellar structure models against realistic 3D radiation-coupled hydrodynamics (RHD) simulations of convection in stellar surface layers, determining the adiabat deep in…
We perform a study of 62 solar analog stars to compute their effective temperatures (Teff) using the Balmer line wing fitting procedure and compare them with Teff values obtained using other commonly employed methods. We use observed…
We present preliminary results on the calculation of synthetic spectra obtained with the stellar model atmospheres developed by Cardona, Crivellari, and Simonneau. These new models have been used as input within the SYNTHE series of codes…
A numerical hydrodynamical model for the evolution of spherically symmetric collapsing clouds, designed for the calculation of the thermal structure of these objects in both the prestellar and protostellar stages of their evolution, is…