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Spectroscopic Classification of M31N 2017-07a and M31N 2017-07d

ATel #10619; S. C. Williams (Lancaster), M. J. Darnley (LJMU)
on 4 Aug 2017; 09:19 UT
Credential Certification: Steven Williams (scw@astro.ljmu.ac.uk)

Subjects: Optical, Nova, Transient

We obtained a spectrum of classical nova candidate M31N 2017-07a (AT2017foa; see TNS) with the SPRAT spectrograph (resolution R ~ 350; Piascik et al. 2014) on the 2-m Liverpool Telescope (Steele et al. 2004) on 2017 Aug 3.07 UT. The spectrum of M31N 2017-07a shows strong Balmer emission lines (Hα, Hβ, Hγ, Hδ) and we measure the FWHM of Hα to be ~1500 km/s. We identify Fe II emission lines, including the 42, 48, 49 and 74 multiplets and O I 7774 Å in emission.

We also obtained a spectrum of nova candidate M31N 2017-07d (PSN J00390448+4046041; see CBAT TOCP) with SPRAT on 2017 Aug 4.14 UT. This spectrum also shows strong Balmer emission (Hα FWHM ~1400 km/s) and numerous Fe II lines, including the same multiplets identified in M31N 2017-07a. In addition, the spectrum of M31N 2017-07d shows O I 7774 Å and Na I (D) emission. The Na I (D) line shows a P Cygni absorption profile.

These spectra confirm both M31N 2017-07a and M31N 2017-07d are classical novae in M31 and members of the Fe II spectroscopic class.