Related papers: A novel analytic atmospheric $T(\tau)$ relation fo…
Context. Adaptive optics (AO) is now a tool commonly deployed in astronomy. The real time correction of the atmospheric turbulence that AO enables allows telescopes to perform close to the diffraction limit at the core of their point spread…
Using experimental data on thermal convection, obtained at a Rayleigh number of 1.5 $\times 10^{11}$, it is shown that the temperature structure functions $<\Delta T_{r}^p>$, where $\Delta T_r$ is the absolute value of the temperature…
We present work on H alpha spectral line characteristics in PHOENIX stellar model atmospheres and their comparison to microlensing observations. We examine in detail the H alpha equivalent width (EW) and the line shape characteristics for…
We present an analytic 1-D radiative-convective model of the thermal structure of planetary atmospheres. Our model assumes that thermal radiative transfer is gray and can be represented by the two-stream approximation. Model atmospheres are…
Present grids of stellar atmosphere models are the workhorses in interpreting stellar observations, and determining their fundamental parameters. These models rely on greatly simplified models of convection, however, lending less predictive…
Two major issues in the specification of the thermospheric density are the definition of proper solar inputs and the empirical modeling of thermosphere response to solar and to geomagnetic forcings. This specification is crucial for the…
Some features of hydro- and thermodynamics, as applied to atmospheres and to stellar structures, are puzzling: 1. The suggestion, first made by Laplace, that our atmosphere has an adiabatic temperature distribution, is confirmed for the…
One of the main obstacles in exoplanet detection when using the radial velocity (RV) technique is the presence of stellar activity signal induced by magnetic regions. In this context, a realistic simulated dataset that can provide…
The mixing length theory (MLT) used to compute the temperature gradient in superadiabatic layers of stellar (interior and atmosphere) models contains in its standard form 4 free parameters. Three parameters are fixed a priori (and define…
All stars exhibit universal central behavior in terms of new homology variables (u,w). In terms of these variables, we obtain simple analytic fits to numerical standard solar models for the core and radiative zones of the ZAMS and present…
We have generated new, self-consistent spectral and atmosphere models for the effective temperature range 600 K to 1300 K thought to encompass the known T dwarfs. For the first time, theoretical models are compared with a {\it family} of…
Convection plays an essential role in the emerging intensity for many stars that will be observed by Gaia. Convective-related surface structures affect the shape, shift, and asymmetry of absorption lines, the phocentric and photometric…
Particle tagging is an efficient, but approximate, technique for using cosmological N-body simulations to model the phase-space evolution of the stellar populations predicted, for example, by a semi-analytic model of galaxy formation. We…
The dynamics and thermal structure of the surface layers of stars with outer convection zones can be studied in some detail by means of numerical simulations of time-dependent compressible convection. In an effort to investigate the…
The negative hydrogen ion H$^-$ is, almost without exception, treated in local thermodynamic equilibrium (LTE) in the modelling of F, G, and K stars, where it is the dominant opacity source in the visual spectral region. This assumption…
The aim of this paper is to provide geoscientists with the most accurate set of the Earth's astro-climatic parameters and daily insolation quantities, able to describe the Short-Term Orbital Forcing (STOF) as represented by the…
We carried out a critical appraisal of the two theoretical models, Kurucz' ATLAS9 and PHOENIX/NextGen, for stellar atmosphere synthesis. Our tests relied on the theoretical fit of SEDs for a sample of 334 target stars along the whole…
The determination of stellar effective temperature ($T_{\mathrm{eff}}$) in F, G, and K stars using H$\alpha$ profile fitting is a quite remarkable and powerful tool, because it practically does not depend on other atmospheric parameters and…
Adiabatic modeling of solar-like oscillations cannot exceed a certain level of precision for fitting individual frequencies. This is known as the problem of near surface effects on the mode physics. We present a theoretical study which…
We present a new stellar atmosphere interpolator which we will use to compute stellar population models based on empirical and/or synthetic spectra. We combined observed and synthetic stellar spectra in order to achieve more or less uniform…