Continued spectroscopic monitoring of V1716 Sco = Nova Sco 2023
ATel #16036; Steve Shore (Univ. Pisa), Stephane Charbonnel, Pascal Le Du, Olivier Garde, Lionel Mulato, Thomas Petit (2SPOT, Chile; ARAS Group), Sean Curry (ARAS Group)
on 12 May 2023; 23:54 UT
Credential Certification: S. N. Shore (shore@df.unipi.it)
Subjects: Cataclysmic Variable, Nova, Transient
Referred to by ATel #: 16069
Our spectroscopic monitoring of the development of PNV J17224490-4137160 = V1716 Sco 2023 (ATel #16002, #16003, #16004, #16006,#16007, #16018 ) is continuing, using low resolution grism (R ~ 1000, 3550-8500A) and medium resolution echelle (R ~11000, 3847-7617A)(ATel #16006). Spectra were obtained on a nearly daily cadence since 2023 Apr. 23. (MJD 60058) through May 11. Absorption at -2200 km/s was present on Na I D until May 1.2, emission persisted symmetrically around the interstellar doublet through May 5.3 when an extended blueward emission, consistent with a weak blend with He I 5876, appeared. The Na I contribution to the blend has diminished and by May 11.2 the profile was consistent with only He I. Helium emission was first weakly detected at He I 7065 profile on May 8.2 with HWZI = 2500 km/s. He I 6678is likely present but severely blended with the red wing of Halpha. Several other He I transitions are, however, not present, particularly He I 5013, 4387, 4471 (although for the last the S/N ratio is poor). He II is absent. The most striking emission lines to appear are [O I]6300,6364, first weakly detected on May 5.2. The profile consists of an ensemble of narrow (~ 400 km/s FWZI) at -1200, -300, +260, +900 km/s, the last being the weakest. These are in striking coincidence with the Hbeta-Hdelta lines, there are coincidences with Halpha throughout the sequence but the contrast is lower. There is no emission at O I 5577. In the low resolution spectra, the O I 7772 and O I 8446 lines are the strongest red transitions, with the 8446/7772 ratio increasing through May 11.0. Even at low resolution, the multiple peak structure is detected on the O I 8446 line. Fe II emission persists, the absorption components on the RMT 42 lines disappeared on May 2. The profiles also show the same emission peaks and HWZI ~ -2000 km/s. Most of the other observable lines are Fe II and related species. The ejecta remain in a low ionization state and are likely still quite optically thick. The lowest density, peripheral regions are beginning to contribute although [O I] (5755/6300+6362) < 0.1 indicates the density is still rather high, consistent with the strength of the O I recombination lines.
ARAS Database: Nova Sco 2023