Stellar ultraviolet (UV) emission serves as a crucial indicator for estimating magnetic activity and evaluating the habitability of exoplanets orbiting stars. In this paper, we present a straightforward method to derive stellar photospheric UV emission for F to M main-sequence stars. By using PARSEC models, we establish relations between near-UV (NUV) and far-UV (FUV) magnitudes from the Galaxy Evolution Explorer (GALEX), NUV magnitudes from the China Space Station Telescope, and stellar effective temperatures and Gaia BP−RP color for different metallicities. Together with the observed sample, we find that for NUV emission, the photospheric contribution to the observed flux is less than 20% for M stars, around 10% to 70% for G stars, and ranges from 30% to 85% for G and F stars. For FUV emission, the photospheric contribution is less than 10−6 for M stars, below 10−4 for K stars, around 10−4 to 10% for G stars, and between 6% and 50% for F stars. Our work enables the simple and effective determination of stellar excess UV emission and the exploration of magnetic activity.
@article{arxiv.2410.11611,
title = {Predicting photospheric UV emission from stellar evolutionary models},
author = {Song Wang and Xue Li and Henggeng Han and Jifeng Liu},
journal= {arXiv preprint arXiv:2410.11611},
year = {2024}
}
Comments
10 pages, 6 figures, 3 tables. Accepted for publication in ApJ