ON THE SPECTROSCOPIC CLASSES OF NOVAE IN M33

• Published in: The Astrophysical journal Vol. 752; no. 2; pp. 1 - 11
• Main Authors: SHAFTER, A. W, DARNLEY, M. J, BODE, M. F, CIARDULLO, R
• Format: Journal Article
• Language: English
• Published: Bristol IOP 20-06-2012
• Subjects: ABSORPTION SPECTROSCOPY; Andromeda Galaxy; ASTRONOMY; ASTROPHYSICS; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CLASSIFICATION; Earth, ocean, space; EMISSION SPECTROSCOPY; Exact sciences and technology; HELIUM; Iron; IRON IONS; MILKY WAY; Milky Way Galaxy; NITROGEN; NOVAE; Spectroscopy; Stellar populations; WHITE DWARF STARS; galaxies: individual (M33); White dwarf stars; Galaxies; Stellar content; Stellar population; Novae; Classification; Cataclysmic variable stars; Milky Way; galaxies: stellar content; novae, cataclysmic variables
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637x/752/2/156

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 sub(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 Fe Eb (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.