Absolute parameters of young stars: HX Velorum

Abstract

We present combined photometric and spectroscopic analyses of the southern multiple star HX Vel. High-resolution spectra of this system were taken at the University of Canterbury Mt. John Observatory in the years 2009-2015. Absolute parameters for HX Vel tend to confirm its young and near-main-sequence nature. We specify the main adopted parameters of the (non-eclipsing) close binary as follows: M₁ = 8.5 ± 1.7, M₂ = 5.4 ± 1.2, R₁ = 5.0 ± 0.3, R₂ = 3.1 ± 0.2, (⊙); T₁ 25 000 ± 1300, T₂ 20 000 ± 2500 (K); systemic M_V -4.2 ± 0.2. These parameters are sensitive to the low inclination, where we find a small disparity between the photometrically optimal 28 ± 2° and an adopted value of 26° that gives better consistency with main-sequence stellar modelling.