Further IRTF SpeX infrared Spectroscopy of  nova N Sgr 2020#2:   CO first overtone seen in emission
C. E. Woodward (University of Minnesota), D. P. K. Banerjee (PRL, India), A. Evans (Keele University), S. Starrfield (Arizona State University), R. M. Wagner (The Ohio State University)
Further to observations reported in ATel # 13801, we report new 0.7-2.5 micron near-infrared spectroscopic observations of the reddened galactic nova N Sgr 2020 No. 2 (equivalently ASASSN-20ga/PGIR20dsv/ZTF20abdpwst/ AT 2020lrv; ATel #13790) obtained on 2020 June 30 UT with the infrared spectrograph SpeX (Rayner et al. 2003, PASP 115, 362) using a 0.5 arcsec x 15 arcsec slit in the SXD (short-cross dispersed) mode (R = 1200) on the NASA IRTF 3.2-m telescope.

All the lines reported in ATel #13081 are present, mostly with deep P-Cygni absorption features, but the emission components are much stronger now. The separation between the emission peak and the absorption minimum is between 1200-1400 km/s for the hydrogen lines. The nova is now past its maximum as shown by the AAVSO lightcurve. A significant change is that helium lines that were not seen earlier, are now present (HeI 1.083 and 2.059 micron) with P Cygni profiles.

Another major development is that first overtone carbon monoxide bands are now clearly seen in emission, though the CO emission is partially contaminated with Pfund lines. This nova is likely to form dust and we encourage further monitoring of its lightcurve.

These observations were conducted under IRTF program 2020A010. CEW acknowledges partial support from NASA grant 80NSSC19K0868.
infra-red,nova