Photovisual light curve and photometric elements of the eclipsing nucleus of the planetary nebula Abell 63
Abstract
The firstV-photoelectric light curve (on theUBV system) of the eclipsing variable UU Sagittae (constituting the central star of a faint planetary nebula Abell 63) was obtained in 1979 with the 74 in. reflector at the Kottamia station of Helwan Observatory in Egypt, and analysed for the photometric elements of the system. Some of the geometrical elements obtained by us differ significantly from those previously deduced by Bondet al. (1978) from theirB-light curve secured in 1976; but there is no reason to suspect from this that any physical change has taken place in the system between 1976 and 1979. The most significant feature of the light curve of UU Sge (in both colours) is the large amplitude of the reflection effect exhibited between minima, as well as the fact that the secondary minimum appears to be almost wholly due to an eclipse of reflected light. This, combined with the depths of the alternate minima observed in both colours, leads us to conclude that the effective temperature of the O-type component is probably not much higher than 30 000 K, while that of the secondary component is not less than 6000 K (corresponding to a subgiant of spectral class close to G0).
- Publication:
-
Astrophysics and Space Science
- Pub Date:
- November 1980
- DOI:
- 10.1007/BF00642368
- Bibcode:
- 1980Ap&SS..73...83B
- Keywords:
-
- Eclipsing Binary Stars;
- Light Curve;
- Planetary Nebulae;
- Variable Stars;
- Astronomical Photometry;
- Eclipses;
- Electrophotometry;
- Astrophysics