Theoretical light curve for a classical nova : nova Cygni 1978.
Abstract
The new opacity (OPAL), which has recently been revised, has a significant enhancement as large as three times the old value and thus rapid acceleration can be expected in mass ejection of novae. Using the new opacity in the optically thick wind theory, I have succeeded in reproducing light curves for the decay phase of classical nova outbursts. Theoretical light curves in visual and UV region are obtained for white dwarfs of mass 0.9, 1.0, 1.1, 1.2, and 1.33 solar mass and compared with observational data of Nova Cygni 1978. The chemical composition of the envelope is assumed to be uniform with X = 0.35, Y = 0.33, C = 0.1, and O = 0.2 for hydrogen, helium, carbon and oxygen by weight, respectively. The best fit model is obtained from simultaneous fitting of visual and UV light curves to the MWD = 1.0 solar mass model. The distance to the star is found to be 2.9 - 3.2 kpc from the comparison of observed apparent magnitude to the theoretical magnitude. Good quality light curves demonstrate the validity of the new OPAL opacity as well as a potential for wide application of the light curve analysis; it will be a useful new method of accurate determination of the white dwarf mass and the distance to the star.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 1994
- Bibcode:
- 1994A&A...281L..49K
- Keywords:
-
- Cygnus Constellation;
- Light Curve;
- Novae;
- Stellar Composition;
- Stellar Envelopes;
- Stellar Models;
- Astronomical Photometry;
- Opacity;
- Stellar Luminosity;
- Stellar Mass Ejection;
- White Dwarf Stars;
- Astronomy