Coronal Line Emission in YZ Reticuli (Nova Reticuli 2020)
ATel #14205; Michael. L. Sitko (Space Science Institute), Richard J. Rudy (Kookoosint Scientific), Ray W. Russell (Observations Unlimited)
on 21 Nov 2020; 03:35 UT
Credential Certification: Richard Rudy (richard.j.rudy@aero.org)
Subjects: Infra-Red, Nova
In this telegram we report infrared spectroscopy of the bright nova YZ Reticuli (Nova Ret 2020). The data were obtained using the SpeX spectrograph at the Infrared Telescope Facility on Mauna Kea, Hawaii on the nights of 7 October 2020 at 13:00-13:17UT and 9 November 2020 at 11:38-12:38UT. The October spectrum spanned the range 0.67-2.5 microns while the November data extended out to 5.2 microns.
YZ Ret was was discovered July 15 by Robert McNaught (CBET 4811). Spectroscopy revealed it to be a classical nova (Carr et al., ATel #13867), most likely of the He/N type (ATel #13874). YZ Ret is also a x-ray source and is being studied intensely in that wavelength regime (ATels #14043 and #14067) Spectroscopy from 18 September showed a rise in excitation and the nova evolving into the nebular phase (Izzo et al., ATel #14048).
Our observations from 7 October showed that YZ Ret had entered the coronal stage, displaying strong infrared lines of [Si VI] and [Si VII], as well as [S VIII] and [Ca VIII]. Multiple lines of N V were also present. The [Si VI] and [Si VII] lines strengthened significantly in the November spectrum. Conversely, strong fluorescently excited O I lines that were present in the October spectrum weakened considerably by November. The He I line at 1.083 microns was the strongest emission feature in both spectra. Most of the emission lines showed double peaked structure with large dips near line center, similar to what was reported for the optical lines (ATel #14067). Full widths at half maxima for the lines were slightly greater than 2000 km/sec. There were no indications of thermal emission from dust at either epoch.
We would like to thank John Rayner and Bobby Bus of the Infrared Telescope Facility for making the time available, and Brian Cabreira and Dave Griep for critical assistance in acquiring the data.
