Characterization of a Sample of Southern M Dwarfs Using Harps and X-shooter Spectra
Abstract
We present the homogeneous analysis of a sample of Southern early-type M dwarfs in the solar neighborhood (d < 60 pc). We used the MCAL technique to derive the effective temperature T eff, metallicity [Fe/H], and activity index i a (H alpha) of 420 M stars using HARPS spectra. The effective temperature T eff, surface gravity log g, metallicity [Fe/H], and projected rotational velocity V rotsini of 153 M0-M6 dwarfs were determined by fitting the observed intermediate-resolution spectra from the VIS arm of VLT/X-shooter with a grid of BT-Settl stellar atmosphere models. We estimated the typical uncertainties of the fit with X-shooter spectra by varying region-to-region results by σT eff ∼ 50 K, σlog g ∼ 0.2, and σ[Fe/H] ∼ 0.2 dex. Photometric verification of T eff for the 295 stars from the HARPS sample and the 61 stars from the X-shooter sample is also provided. We compared our results from different methods to estimate absolute uncertainty in determining the physical properties of M dwarfs.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2019
- DOI:
- 10.3847/1538-4357/ab1fe9
- Bibcode:
- 2019ApJ...878..134K
- Keywords:
-
- stars: abundances;
- stars: fundamental parameters;
- stars: low-mass;
- techniques: spectroscopic