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ATEL # 1832; A. W. Shafter (SDSU), R. Ciardullo (PSU), M. F. Bode, M. J. Darnley (Liverpool JMU, UK), K. A. Misselt (U. Arizona)
on 7 Nov 2008; 2:30 UT
Password Certification: Allen W. Shafter (firstname.lastname@example.org)
Subjects: Optical, Nova, Transients
The recent M31 nova candidate, M31N 2008-11a, was discovered by K. Nishiyama and F. Kabashima on 2008 November 04.534 UT, and independently by K. Hornoch on 2008 November 4.718 UT. At our request, a spectrum (420-720 nm) of M31N 2008-11a was obtained approximately two days later on 2008 November 6.3 UT by J. Caldwell and C. Terrazas with the 9.2m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph). The spectrum of M31N 2008-11a is dominated by broad Balmer and He I emission features (FWHM H&alpha ~ 5000 km/s) superimposed on a flat continuum. Other weaker emission features are also present, including a blend of N III (4640Å) and He II (4686Å). In addition, there are two broad emission features to the red of the H&beta line. The first feature is likely a blend of N II (5001Å), He I (5016Å), and possibly Fe II (5018Å), while a second feature near 5170Å is likely due solely to Fe II. We are tempted to classify M31N 2008-11a as a He/N nova, but given the likely detection of Fe II emission, it would be more accurate to classify it as a "hybrid" nova (see Williams, 1992, AJ, 104, 725). Hybrid novae often evolve into He/N novae within a few weeks after eruption, and further spectroscopic observations are encouraged to see if M31N 2008-11a follows this path.