Spectroscopy of Galactic Nova V5853 Sgr (ASASSN-16ig)
ATel #9613; S. C. Williams (Lancaster), M. J. Darnley (LJMU)
on 11 Oct 2016; 13:36 UT
Credential Certification: Steven Williams (scw@astro.ljmu.ac.uk)
Subjects: Optical, Nova, Transient
We have been following Galactic nova V5853 Sgr (ASASSN-16ig; see ATels #9343, #9352, #9359, #9375, #9377, #9379, CBET 4295, 4299) with the FRODOSpec spectrograph (Barnsley et al. 2012) on the 2.0m Liverpool Telescope (LT; Steele et al. 2004) using the higher resolution mode, which gives a wavelength coverage of 3900 to 5100Å and 5900 to 8000Å, with a resolution of R ~ 5400. Here we report the results of our most recent spectrum, taken 2016 Oct 9.83 UT.
The spectrum shows strong Hα emission, which peaks at the rest wavelength, but also has a secondary peak at a velocity of +500 km/s. There is also strong O I (7774 Å) emission which shows a blueshifted detached P-Cygni absorption profile at -2800 km/s. Absorption also appears to accompany the Hα line, but this is somewhat blended with the N II (6482 Å) emission. A weak absorption component at -2800 km/s is also detected on this N II line. The [O I] emission lines at 6300 and 6364 Å are clearly seen in the 2016 Oct 9 spectrum. We see He I (6678 and 7065 Å) and C II (7235 Å) in emission, as well as a feature at ~7115 Å, which is likely due to C I. The N I (3) triplet is still detected, now only in emission, and unlike the early spectra, it is no longer one of the strongest features. The S/N in the blue arm (3900 to 5100Å) is poor due to the the relatively high reddening, but we do detect Hβ and N III (4638 Å) emission lines.
The nova is now very difficult to observe from northern latitudes such as that of the LT. Further observations of Nova V5853 Sgr are encouraged before it becomes unobservable due to the Sun.
