Spectroscopic classification and Gaia DR2 parallaxes of new nearby white dwarfs among selected blue proper motion stars
Aims: With our low-resolution spectroscopic observing programme for selected blue proper motion stars, we tried to find new white dwarfs (WDs) in the solar neighbourhood.
Methods: We used the Lépine & Shara Proper Motion (LSPM) catalogue with a lower proper motion limit of 150 mas yr-1 and the Second US Naval Observatory CCD Astrograph Catalog (UCAC2) for proper motions down to about 90 mas yr-1. The LSPM and UCAC2 photometry was combined with Two Micron All Sky Survey (2MASS) near-infrared (NIR) photometry. Targets selected according to their blue optical-to-NIR and NIR colours were observed mainly at Calar Alto. The spectra were classified by comparison with a large number of already known comparison objects, including WDs, simultaneously observed within our programme. Gaia DR2 parallaxes and colours were used to confirm or reject spectroscopic WD candidates and to derive improved effective temperatures.
Results: We found ten new WDs at distances between 24.4 pc and 79.8 pc, including six hot DA WDs:
Astronomy and Astrophysics
- Pub Date:
- November 2018
- techniques: spectroscopic;
- proper motions;
- white dwarfs;
- solar neighborhood;
- Astrophysics - Solar and Stellar Astrophysics
- 14 pages, 13 figures, accepted for publication in Astronomy and Astrophysics