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Spectroscopic Observations of the M31 nova PNV J00425571+4117524 and the M31 nova candidate PNV J00452885+4154094

ATel #3727; A. W. Shafter (SDSU), R. Ciardullo (PSU), M. J. Darnley, M. F. Bode (Liverpool JMU, UK)
on 31 Oct 2011; 06:22 UT
Credential Certification: Allen W. Shafter (aws@nova.sdsu.edu)

Subjects: Optical, Nova, Transient

Referred to by ATel #: 3728, 4503, 5607, 5611

We report spectroscopic observations of the recent M31 nova candidate PNV J00452885+4154094 (discovered by S. Korotkiy and L. Elenin on 2011 Oct. 22.460 UT), as well as additional spectroscopic observations of the confirmed M31 nova, PNV J00425571+4117524 (ATels #3693, #3699, #3712, #3725). The latter observations were obtained in order to determine if PNV J00425571+4117524, originally classified as an Fe IIb nova by Shafter et al. (ATel #3699) based on a spectrum obtained ~1.5 days after discovery, might evolve into a Hybrid system characterized by a He/N-type spectrum. At our request, spectra of both objects (410–950 nm) were obtained by J. Caldwell on 2011 Oct. 29.33 UT with the 9.2m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph).

The spectrum of the nova candidate, PNV J00452885+4154094, reveals prominent TiO bands at 705.4 nm and 766.6 nm superimposed on a very red continuum, indicating that the object is a long-period (Mira) variable in M31, and not a nova.

Our follow-up spectrum of the confirmed nova, PNV J00425571+4117524, taken ~10 days post-discovery, now reveals narrow Balmer, Fe II (multiplets 37,38,42,48,49), He I (λ 667.8 nm, λ 706.5 nm, and possibly λ 587.6 nm blended with Na D), and Ca II infrared triplet (λ 849.8 nm, λ 854.2 nm, λ 866.2 nm) emission lines (FWHM Hα ~ 900 km/s; EW Hα ~ -17 nm) superimposed on a relatively flat continuum. These observations, along with the recent spectrum obtained by Barsukova et al. (ATel #3725), suggest that the object is not a Hybrid nova, but rather an (unusual) Fe II nova with narrowing lines and emerging He I emission.

A.W.S. thanks the NSF for support through AST-1009566

HET Spectra of Local Group Novae