2013/09/18 by A. S. Rajpurohit, Rajpurohit, A. S., C. Reylé +6
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astronomy and Astrophysical Research #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.48550/arxiv.1309.4604
6 pages, 4 figures, to be appear in Proceedings of French Astronomical Society Meeting (SF2A-2013)
arxiv created 2013/09/18 · openalex publication_date 2013/09/18 · arxiv updated 2013/09/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
M subdwarfs are metal poor and cool stars. They are important probes of the old galactic populations. However, they remain elusive due to their low luminosity. Observational and modeling efforts are required to fully understand the physics and to investigate the effect of metallicity in their cool atmo- spheres. We perform a detail study of a sample of subdwarfs to determine their stellar parameters and constrain the atmosphere models. We present UVES/VLT high resolution spectra of 21 M subdwarfs. Our atlas covers the optical region from 6400°A up to the near infrared at 10000°A. We show spectral details of cool atmospheres at very high resolution (R = 40 000) and compare with synthetic spectra computed from the recent BT-Settl atmosphere models. Our comparison shows that molecular features (TiO, VO, CaH), and atomic features (Fe, Ti, Na, K) are well fitted by current models. We produce an effective temperature versus spectral type relation all over the subdwarf spectral sequence.