First spectroscopic observations of TCP J18292290-1430460 (Nova Sct 2018): an optically thick classical nova
ATel #11802; Olivier Gard, Umberto Sollecchia (ARAS Group)
on 1 Jul 2018; 02:10 UT
Distributed as an Instant Email Notice Novae
Credential Certification: S. N. Shore (shore@df.unipi.it)
We report early low and echelle spectroscopy of the newly discovered transient TCP J18292290-1430460 (AAVSO Alert 621695, discovered by Yukio Sakurai on 2018 Jun 29.577UT) The observations confirm this as a classical nova. Echelle spectra were obtained by Olivier Garde (Observatoire de la Tourbiere, France, RC400 Astrosib-Eshel-ATIK460EX2018)Jun Jun 30.861UT (R ~11000), covering 4250-7585, 10x1200 sec); the average S/N > 50 at 6000A. Low resolution grim spectra were obtained by Umberto Sollecchia (L'Aquila, Italy; Alpy600, R~ 500, 3769-7288A, 5x960 sec exposure time), centered at 2018 Jun 30.874UT. The overall appearance of the spectrum is of strong, overlapping absorption features with few prominent emission lines (aside from Halpha) and high interstellar extinction. However, there are some notable features that warrant reporting. P Cyg structure is present on Fe II 6456, 5169, 4923, 5018 (the usual), v_max = -800 km/s, nearly symmetric absorption and emission in higher multiplets. Hbeta shows deep absorption but no emission, Halpha displays very strong emission (em/abs ~1) with an unsaturated (ejecta-like) absorption extending to -1700 km/s (similarly for the red wing). No He I lines are present in the spectrum at this stage. The optical Mg I triplet (5167,72,83) shows displaced absorption at the same velocity as Na I D1,D2, about -700 km/s, with the Na I D lines well separated even in the displaced components. There appears to be weak associated emission at Na I; the ISM absorption is at about +20 km/s (several components seem to be present, the lines are not completely saturated). Mg II is absent. The Si II 6347,71 doublet shows weak P Cyg, v_max=-800 km/s on both components. There are many overlapping absorption transitions, the spectrum is typical of a classical nova in the optically thick (Fe-curtain) stage. Overall, the reality of the individual features is confirmed with the low resolution Alpy600 spectrum taken almost simultaneously. Observations are continuing, all spectra are publicly available though the ARAS database http://www.astrosurf.com/aras/Aras_DataBase/Novae/2018_NovaSct2018.htm
ARAS spectroscopic database
