Contributed Talk - Splinter HotStars

Friday, 16 September 2022, 14:40   (SFG 1030 / virtual HotStars)

Fundamental stellar parameters for 222 B-type stars for the X-shooter Spectral Library

Cormac Larkin, Kristiina Verro, Anaïs Gonneau, Scott Trager
ARI/MPIK/MPIA/RUG, RUG, Univ. Cambridge, RUG

Stellar population models are building blocks for furthering our understanding of galaxies. With short lifetimes and high bolometric luminosities, B-type stars dominate the first few to tens of Myr of a stellar population, and strongly influence the chemical evolution of their environment via nucleosynthesis of metals and supernovae explosions. Currently, empirical spectral libraries such as the X-shooter Spectral Library (XSL) have a paucity of these stars compared to cooler stars, making it difficult to probe younger populations. We use the MIDE3700 code to find effective temperatures Teff and surface gravities log g via the BCD method for 222 B-type stars in the XSL calibration archive in preparation for their inclusion as an extension to the XSL itself. We find agreement to within ∼ 0.1 σ log Teff and ∼ 0.25 σ log g between our results and a sample of literature stars. We populate a previously bare region of the XSL Hertzsprung-Russell diagram in the ranges 9000 ≤ Teff ≤ 23000 and 2.8 ≤ log g ≤ 4.0, and extend the lower age limit for XSL stellar population models by up to a factor ∼ 10 for [Fe/H] = -1.2, and a factor ∼ 2 for Solar metallicity.