BE Ursae Majoris: Precataclysmic Binary System and Planetary Nucleus
Abstract
This paper presents new spectrophotometric observations and a new analysis of the hot and cool components of the evolved binary system BE Ursae Majoris, and we report the discovery of a planetary nebula around it. The primary star can be classified as a subdwarf O or borderline DAO white dwarf with Teff = 105,000 K +/- 11,000 K, log g = 6.5 +/- 0.25, based on Non Local Thermodynamic Equilibrium (NLTE) model atmosphere profile fits to the H and He II lines. Observations of the secondary during eclipse indicate a spectral type of K5. Its estimated brightness during eclipse is consistent with a main-sequence star of K5 at the distance of 1.9 kpc derived from analysis of the primary star. The nebula is roughly circular with a diameter of 3 min. This corresponds to a physical diameter of 1.5 pc at the estimated distance.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1995
- DOI:
- 10.1086/175366
- Bibcode:
- 1995ApJ...441..424L
- Keywords:
-
- Cataclysmic Variables;
- Eclipsing Binary Stars;
- K Stars;
- Planetary Nebulae;
- White Dwarf Stars;
- Atmospheric Models;
- Local Thermodynamic Equilibrium;
- Stellar Models;
- Stellar Spectrophotometry;
- Astronomy