Spectroscopic Confirmation of the 2021 Eruption of the Recurrent Nova M31N 2008-12a
ATel #15036; R. M. Wagner (LBTO/Ohio State U.), C. E. Woodward (U. Minnesota), S. Starrfield (Arizona State U.), B. Rothberg (LBTO), O. Kuhn (LBTO)
on 15 Nov 2021; 09:13 UT
Credential Certification: R. Mark Wagner (rmw@as.arizona.edu)
Subjects: Optical, Nova, Transient
In ATEL #15034, Itagaki et al. reported the discovery of the predicted 2021 eruption of the recurrent M31 nova M31N 2008-12a on 2021 Nov 14.3784 UT at an unfiltered magnitude of 18.7 at the Itagaki Observatory. We confirm the 2021 eruption based on an optical spectrum (range: 320-1010 nm; resolution 0.35 nm) obtained on 2021 Nov 15.2071 UT with the 2 x 8.4 m Large Binocular Telescope (+MODS). The spectrum exhibits broad emission lines of the Balmer series of hydrogen (Hα, Hβ, Hγ, and Hδ), He I (447.1, 492.2, 501.5, 587.5, 667.8, and 706.5 nm), N III (463.8 nm), and N II (568.0 nm) superposed on a blue continuum. We measure the FWHM of Hα and Hβ emission to be 2560 and 2300 km/s respectively and the FWZI of Hβ emission to be about 4420 km/s. The spectrum is similar to the early optical spectra of M31N 2008-12a presented by Darnley et al. (2015, A&A, 580, A45) for the 2014 eruption and by Henze et al. (2018, ApJ, 857, 68) for the 2016 eruption. Our observations are continuing.
