The UBV Color Evolution of Classical Novae. III. Time-stretched Color-Magnitude Diagram of Novae in Outburst
Abstract
We propose a modified color-magnitude diagram for novae in outburst, i.e., (B - V)0 versus (M V - 2.5 log f s), where f s is the time-scaling factor of a (target) nova against a comparison (template) nova, (B - V)0 is the intrinsic B - V color, and M V is the absolute V magnitude. We dub it the time-stretched color-magnitude diagram. We carefully reanalyzed 20 novae based on the time-stretching method and revised their extinctions E(B - V), distance moduli in the V-band (m - M) V , distances d, and time-scaling factors f s against the template nova LV Vul. We have found that these 20 nova outburst tracks broadly follow one of the two template tracks, the LV Vul/V1668 Cyg or V1500 Cyg/V1974 Cyg group, in the time-stretched color-magnitude diagram. In addition, we estimate the white dwarf masses and (m - M) V of the novae by directly fitting the absolute V model light curves (M V ) with observational apparent V magnitudes (m V ). A good agreement of the two estimates of (m - M) V confirms the consistency of the time-stretched color-magnitude diagram. Our distance estimates are in good agreement with the results of Gaia Data Release 2.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- March 2019
- DOI:
- 10.3847/1538-4365/ab0202
- arXiv:
- arXiv:1902.10919
- Bibcode:
- 2019ApJS..241....4H
- Keywords:
-
- novae;
- cataclysmic variables;
- stars: individual: V574 Pup;
- V679 Car;
- V1369 Cen;
- V5666 Sgr;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 89 pages including 52 figures, in ApJS, 241, 4 (2019)