Related papers: Detailed Opacity Calculations for Stellar Models
The free electron model with Boltzmann statistics for spherical low-density plasmas (Scientific Reports 9. 20384, 2019) is developed further by numerical calculations with asymptotic relations obtaining the density of electrons, mass…
Galaxy-galaxy lensing is a powerful probe of the relation between galaxies and dark matter halos, but its theoretical interpretation requires a careful modeling of various contributions, such as the contribution from central and satellite…
We develop a method of analyzing radio frequency spectral line observations to derive data on the temperature, density, velocity, and molecular abundance of the emitting gas. The method incorporates a radiative transfer code with a new…
We report on the development of an implicit multi-D hydrodynamic code for stellar evolution. We present two test-cases relevant for the first scientific goal of the code: the simulation of convection in pulsating stars. First results on a…
The interest in using optical transition radiation (OTR) in high energy (multiGeV) beam diagnostics has motivated theoretical and experimental investigations on the limitations brought by diffraction on the attainable resolution. This paper…
The results of spectral observations in the $\sim 84-92$ GHz frequency range of six objects in the southern sky containing dense cores and associated with regions of massive stars and star clusters formation are presented. The observations…
Modeling of the spectral line energy distribution (SLED) of the CO molecule can reveal the physical conditions (temperature, density) of molecular gas in Galactic clouds and other galaxies. Recently, the Herschel Space Observatory and ALMA…
The opacity due to photodissociation of 24MgH is investigated in the atmospheres of cool stars. The lowest two electronic transitions A 2Pi -- X 2Sigma+ and B' 2Sigma+ -- X 2 Sigma+ are considered where the cross sections for the latter…
The dust in galaxies makes radiation transport calculations in them absolutely necessary. It is not only common practice in Astrophysics, but also wisdom, to try to make as simple models as possible to simulate physical systems. For spiral…
Recently 3D hydrodynamical simulations of stellar surface convection have become feasible thanks to advances in computer technology and efficient numerical algorithms. Available observational diagnostics indicate that these models are…
In a molecular cloud dust opacity typically dominates over gas opacity, yet in the vicinities of forming stars dust is depleted, and gas is the sole provider of opacity. In the optically thin circumstellar environments the radiation…
We present the result of a proof-of-concept simulation designed to classify LEO satellites based on their occultations of background stars. We generate satellite shapes drawn from two broad shape classes, 'boxwing' and 'square'. We then…
In accelerating and supersonic media, the interaction of photons with spectral lines can be of ultimate importance. However, fully accounting for such line forces currently can only be done by specialised codes in 1-D steady-state flows.…
Asteroseismology involves using the resonant frequencies of a star to infer details about its internal structure and evolutionary state. Oscillation frequencies are most useful when accompanied by accurate measurements of the more…
We present new calculations of Rosseland and Planck gaseous mean opacities relevant to the atmospheres of giant planets and ultracool dwarfs. Such calculations are used in modeling the atmospheres, interiors, formation, and evolution of…
Radiative shocks are found in various astrophysical objects and particularly at different stages of stellar evolution. Studying radiative shocks, their topology, and thermodynamical properties is therefore a starting point to understanding…
We present a comprehensive analysis of high-resolution, far-UV HST/STIS, FUSE, and optical spectra of 17 O stars in the SMC. Our analysis is based on NLTE metal line-blanketed model atmospheres calculated with our NLTE code TLUSTY. We…
While optical and quantum efficiency are on the rise, and spectrographs becoming massively multiplexed, measuring spectral energy distributions of astronomical sources with accuracy remains a challenge. In addition to atmospheric…
The optical properties of plasmas with high densities and medium temperatures are analyzed by the use of a free electron model with Fermi-Dirac statistics. For the present collisional plasma the frequency of electron-ion collision is very…
Previous computations of low temperature Rosseland and Planck mean opacities from Alexander & Ferguson (1994) are updated and expanded. The new computations include a more complete equation of state with more grain species and updated…