Speaker
Description
We present results from an ongoing high-resolution spectroscopic survey of hot subdwarf stars observed with the Vilnius University Echelle Spectrograph (VUES) mounted on the 1.65 m telescope at Molėtai Astronomical Observatory in Lithuania. Building on our previous large-scale study of ~20,000 Gaia XP spectra, we use medium-high-resolution (R≈36,000) optical spectra to derive atmospheric parameters and assess binarity through detailed line-profile analysis. This data enable us to validate and refine classifications obtained from low-resolution surveys such as Gaia XP (R≈50) and LAMOST (R≈1800). We compare effective temperatures, helium abundances, and spectral subtypes (sdB vs. hot/He-rich) across different resolutions, quantifying systematic biases and degeneracies inherent to low-resolution spectra. Our results demonstrate the diagnostic power of high-resolution follow-up to calibrate machine-learning classifications and to better constrain the evolutionary channels of hot subdwarfs.