Strong Dust Emission in Nova CMa 2018
ATel #12316; Jon Mauerhan, Richard Rudy, Sloane Wiktorowicz, John Subasavage, Daryl Kim, Kirk Crawford (Aerospace Corporation); Chick Woodward (University of Minnesota); Ray Russell (Observations Unlimited)
on 21 Dec 2018; 00:19 UT
Credential Certification: Jon Mauerhan (jon.c.mauerhan@aero.org)
Subjects: Infra-Red, Optical, Nova, Transient
We report further 1-13 micron infrared spectroscopy of Nova Canis Majoris (ATel 11565; CBET 4499) obtained with The Aerospace Corporation's Broadband Array Spectrograph System (BASS) and the Spex instrument on NASAâs IRTF 3-m telescope during the period 2018 December 08 through 10 UT. Earlier 0.47-2.5 micron spectroscopy was obtained on 2018 Oct 20 using the Aerospace Corporationâs Visible and Near-Infrared Imaging Spectrograph on the 3-m Shane reflector at the University of Californiaâs Lick Observatory. The novaâs infrared spectral energy distribution is dominated by a strong thermal continuum from dust, which exhibits a peak flux of approximately 2 Jy near 5 microns and is well matched by a blackbody of temperature 770 K. A less certain temperature derived from the October near-infrared data is 720 K, indicating that the dust has not cooled and has possibly warmed in the interval. An additional broad emission bump is detected near 8.1 microns, which resembles unidentified infrared (UIR) features previously observed in Nova Cassiopeiae 1993 (aka V705 Cas; Evans et al. 2005, MNRAS, 360, 1483) and V2362 Cyg (Lynch et al. 2008, AJ, 136, 1815). The near-infrared spectrum of the atomic emission lines increased in excitation between the October and December observations. He II and Rydberg lines were present in the former while in the latter, coronal lines, most notably [Si VI] at 1.9645 microns, have emerged. Continued monitoring of this infrared-bright nova is encouraged.
