Near-infrared observations of nova V2891 Cygni (AT 2019qwf)
ATel #13301; Vishal Joshi, D. P.K. Banerjee and Mudit Srivastava; Physical Research Laboratory, Ahmedabad, India
on 21 Nov 2019; 07:09 UT
Credential Certification: Dipankar P.K. Banerjee (firstname.lastname@example.org)
Subjects: Infra-Red, Nova
We report on near-infrared spectroscopy and photometry of Nova V2891 Cygni (AT 2019qwf) discovered in 2019 mid September ( ATel #13130, ATel #13149). The object initially displayed a F type (Flat) light curve which has been followed by a slow brightening over the last few weeks. The nova has been followed in the optical (spectroscopy reported by Srivastava et al., ATel #13258 and U. Munari, ATel #13283) and also been shown to have an observed photometric period of 3.7991 +/- 0.0048 hr from observations in the Cousins I band (R. E. Schmidt, CBET 4694).
The NIR observations were made using the Near-infrared Camera Spectrograph (NICS) deployed on the 1.2m Mount Abu telescope of the Physical Research Laboratory, India. Spectra were obtained on 2019 November 18.68 UT in the 0.85 to 2.45 micron region at R ~ 1000. The spectra display narrow emission lines of H, C, N and O typically seen in the Fe II class of novae. The HeI 1.083 micron line is present but weak. Although no first overtone CO emission is seen in the K band, there are lines of Na and Mg seen which, as we have argued earlier (Das et al. 2008, MNRAS, 391, 1874), suggest that this nova could form dust in the future. Photometry yields J = 9.98 +/- 0.02, H = 8.87 +/- 0.03 and Ks = 7.66 +/- 0.02. The distinctive and interesting light curve warrants further observations.