Modelling the Spectra of Planets, Brown Dwarfs and Stars using VSTAR

TL;DR

VSTAR is a versatile, modular software tool that accurately models the spectra of planets, brown dwarfs, and stars by combining detailed molecular absorption and multiple scattering in radiative transfer calculations.

Contribution

It introduces a new comprehensive spectral modeling software that integrates line-by-line absorption, scattering, and chemical equilibrium for diverse astronomical objects.

Findings

VSTAR accurately reproduces observed spectra of planets and stars.

The software's detailed line database enhances spectral prediction precision.

Benchmark tests confirm VSTAR's reliability and versatility.

Abstract

We describe a new software package capable of predicting the spectra of solar-system planets, exoplanets, brown dwarfs and cool stars. The Versatile Software for Transfer of Atmospheric Radiation (VSTAR) code combines a line-by-line approach to molecular and atomic absorption with a full multiple scattering treatment of radiative transfer. VSTAR is a modular system incorporating an ionization and chemical equilibrium model, a comprehensive treatment of spectral line absorption using a database of more than 2.9 billion spectral lines, a scattering package and a radiative transfer module. We test the methods by comparison with other models and benchmark calculations. We present examples of the use of VSTAR to model the spectra of terrestrial and giant planet in our own solar system, brown dwarfs and cool stars.