New Model Atmospheres: Testing the Solar Spectrum in the UV

TL;DR

This paper introduces new stellar atmosphere models capable of detailed UV spectrum synthesis, demonstrating their successful integration with existing codes and highlighting the importance of outer atmospheric layers in UV spectral features.

Contribution

The paper presents the development and initial testing of extended stellar atmosphere models that reach very low optical depths, enabling more accurate UV spectrum simulations.

Findings

Successfully computed high-resolution synthetic solar spectrum in UV range.

Outer atmospheric layers significantly influence mid-UV spectral properties.

Extended models are promising tools for UV stellar atmosphere analysis.

Abstract

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 developed by Kurucz. As a first step we have tested if SYNTHE is able to handle these models which go down to log tau(Ross)= -13. We have successfully calculated a synthetic solar spectrum in the wavelength region 2000--4500 A at high resolution (R=522,000). Within this initial test we have found that layers at optical depths with log tau(Ross) < -7 significantly affect the mid-UV properties of a synthetic spectrum computed from a solar model. We anticipate that these new extended models will be a valuable tool for the analysis of UV stellar light arising from the outermost layers of the atmospheres.