We report the initial results from an ongoing multi-year spectroscopic survey of novae in M33. The survey resulted in the spectroscopic classification of six novae (M33N 2006-09a, 2007-09a, 2009-01a, 2010-10a, 2010-11a, and 2011-12a) and a determination of rates of decline (t 2 times) for four of them (2006-09a, 2007-09a, 2009-01a, and 2010-10a). When these data are combined with existing spectroscopic data for two additional M33 novae (2003-09a and 2008-02a), we find that five of the eight novae with available spectroscopic class appear to be members of either the He/N or FeIIb (hybrid) classes, with only two clear members of the FeII spectroscopic class. This initial finding is very different from what would be expected based on the results for M31 and the Galaxy where FeII novae dominate, and the He/N and FeIIb classes together make up only 20% of the total. It is plausible that the increased fraction of He/N and FeIIb novae observed in M33 thus far may be the result of the younger stellar population that dominates this galaxy, which is expected to produce novae that harbor generally more massive white dwarfs than those typically associated with novae in M31 or the Milky Way.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science