Modeling Stellar Atmospheres with a Spherically Symmetric Version of the Atlas Code: Testing the Code by Comparisons to Interferometric Observations and PHOENIX Models

TL;DR

This paper introduces SATLAS, a spherically symmetric stellar atmosphere modeling code based on ATLAS, validated against interferometric data and PHOENIX models, improving interpretation of stellar observations.

Contribution

Development of SATLAS, a new spherical stellar atmosphere code derived from ATLAS, tested and validated against interferometric data and PHOENIX models for low gravity stars.

Findings

SATLAS models match observed interferometric visibilities.

SATLAS atmospheric structures agree with PHOENIX models.

Small differences observed at large atmospheric depths.

Abstract

One of the current opportunities for stellar atmospheric modeling is the interpretation of optical interferometric data of stars. Starting from the robust, open source ATLAS atmospheric code (Kurucz, 1979), we have developed a spherically symmetric code, SATLAS, as a new option for modeling stellar atmospheres of low gravity stars. The SATLAS code is tested against both interferometric observations of M giants by Wittkowski and collaborators, and spherically symmetric M giant NextGen models from the PHOENIX code. The SATLAS models predict interferometric visibilities that agree with the observed visibilities and with predicted visibilities, and the SATLAS atmospheric structures also agree with those from spherical PHOENIX models, with just small differences in temperature and pressure at large depths in the atmospheres.