Abstract

Contributed Talk - Splinter JungeAG

Tuesday, 10 September 2024, 14:44   (S25)

Spectroscopic analysis of hot subluminous stars from the Hamburg Quasar Survey: New atmospheric- and stellar parameters

Lennard Kufleitner
FAU Erlangen-Nürnberg

As part of my bachelor's thesis, I performed an analysis of a sample of hot subdwarfs of spectral types sdB and sdOB from the spectroscopic follow-up to the Hamburg Quasar Survey (HQS) which was identified by Edelmann et al. (2003). By performing a spectroscopic analysis of the spectra obtained during the follow-up new atmospheric parameters are derived with a new grid of model spectra and a global fitting method, both different from the previous study by Edelmann et al. (2003). Independent spectra were taken from the SDSS/LAMOST surveys and spectroscopically analyzed, which showed no systematic differences to the spectra from the HQS follow-up. A photometric fit is performed by using the data from many photometric surveys to derive the stellar parameters radius, luminosity and mass for this sample for the first time by combining the information obtained from the spectroscopy and photometry with the parallaxes measured by the Gaia satellite. The stellar parameters which were derived for the non-composite stars are found to be in agreement with predictions by canonical evolution models with a median of the mass distribution of 0.433 M☉, radii in the range of 0.1 to 0.3 R☉ and luminosities in the range of 10 to 30 L☉. The HQS sample forms a reference sample for large spectroscopic surveys like 4MOST to come.