On the Spectroscopic Classes of Novae in M33
  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 5 of the 8 novae with available spectroscopic class appear to be members
of either the He/N or Fe IIb (hybrid) classes, with only two clear members of
the Fe II spectroscopic class. This initial finding is very different from what
would be expected based on the results for M31 and the Galaxy where Fe II novae
dominate, and the He/N and Fe IIb classes together make up only ~20% of the
total. It is plausible that the increased fraction of He/N and Fe IIb 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.
