Dust formation in V1112 Per (Nova Per 2020)
ATel #14338; D. P. K. Banerjee (PRL, India), Vishal Joshi (PRL, India), G. C. Anupama (IIA, India), U. Munari (INAF Padova), K. De (Caltech), M. M. Kasliwal (Caltech), Mudit Srivastava (PRL), Sandipan Borthakur (PRL) and the DOT team, Devasthal, India.
on 20 Jan 2021; 19:49 UT
Credential Certification: Dipankar P.K. Banerjee (dpkb12345@gmail.com)
Subjects: Infra-Red, Nova
We report near-infrared JHK band photometry of Nova Per 2020 on 15.56 Jan 2021 UT obtained with TIRCAM2 (Baug, T. et al. 2018, JAI, 7) on the 3.6-m Devasthal Optical Telescope (DOT). The nova was discovered in outburst on Nov 25.807 UT as TCP J04291884+4354232 by Seiji Ueda, Japan (ATel #14229). The brightness of the nova had been seen to decline rather sharply in the B and V bands, by about 4-5 magnitudes since ~ 5 Jan 2021, with a marked reddening of colors suggesting the onset of dust formation. The observations reported here confirm this. Our photometry, done by defocussing the star to avoid saturation of the detector, and calibrated against 2MASS field stars and the standard star A0V star HD 18881, yields values of J = 8.25 +/- 0.1, H = 6.4 +/- 0.3 and K = 4.6 +/- 0.4. The J magnitude is consistent with the fading trend seen in the preceding and succeeding observations of J = 8.15 +/- 0.01 on Jan 14 and J = 8.54 +/- 0.01 on Jan 19 made from the Palomar Gattini-IR survey (Moore & Kasliwal 2019).
Considering novae have (B- V) ~ 0.23 and 0.0 respectively at maximum and t2 (Van den Bergh and Younger, 1987), the reddening E(B-V) is estimated to be ~ 0.60-0.65 (this is a preliminary estimate, courtesy data from AAVSO light curves). Other estimates for E(B-V) are in the range 0.77-0.82 using the strength(s) of the interstellar NaI doublet and DIB features (ATel #14229). Correcting for the extinction accordingly, the dereddened (J-K) color of the nova is large and in the range 3.2 to 3.3 which clearly indicates that the nova has formed dust. Further monitoring of V1112 Per is encouraged. We thank the DOT team (Aryabhatta Research Institute of Observational Sciences; ARIES) for approving and facilitating early observations of the nova and also thank the staff at the Devasthal Observatory for their support.
