Continuing echelle spectroscopy of the classical nova TCP J18292290-1430460 = Nova Sct 2018

ATel #11826; Olivier Garde (ASAS Group)
on 8 Jul 2018; 18:21 UT
Distributed as an Instant Email Notice Novae
Credential Certification: S. N. Shore (shore@df.unipi.it)

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We report continuing echelle spectroscopy of the newly discovered classical nova TCP J18292290-1430460 = Nova Sct 2018 (ATel #11802, #11817). Echelle spectra were obtained 2018 Jul 7.85 UT (HJD 58307.4238) at Observatoire de la Tourbiere, France, RC400 Astrosib-Eshel-ATIK460EX2018 with a resolution of ~11000 covering 4250-7585, 10x1200 sec; the average S/N ~ 40 at 6000A. The Na I D lines show two absorption features, -1500 km/s and -820 km/s, with the higher velocity absorption stronger but approximately the same velocity width. There is still strong emission in the line extending to +2000 km/s. The Mg I triplet shows virtually the same profile as Na I but the overlap of the multiplet components changes the absorption widths; Na I 5686 may also be present. Fe II RMT 42 lines show two components of unequal absorption strength (4923, -1600 km/s, 3.1A; -800, 1.3A; 5018, 2.2A,1.4A; 5169, 2.5A, 1.5A:) with the velocity widths 600 km/s and 400 km/s, respectively. The emission wing is similarly extended to +200 km/s, and structure is beginning to appear (double peak) at low velocity (-350,+500 km/s). Si II 6347,6371 show almost identical absorption features as Fe II but neither line shows emission. Al II 6237 is possibly present, blended with Fe II 6248, with weaker absorption but with a similar velocity extent as Na I. The Balmer lines show the same structures as Fe II with a broader high velocity absorption component. The same two peaks at low velocity are present on Halpha and Hbeta, although less visible on Halpha; the emission peak ratio is about 3.6; the spectra were normalized and uncorrected for interstellar extinction. Although not displaying any emission component, He I 5876, 6678 show a broad detached absorption feature at -1500 km/s (full width at continuum ~ 500 km/s). This has been observed in several novae at this early stage, notably V339 Del. This feature is a broad absorption to the blue of the Na I narrower features. Neither [O I] nor [N II] are visible. The dominant emission lines are still from singly ionized metals, few if any forbidden lines are present (e.g. [Fe II] 5159 is absent) and the nova appears to be in a later stage of the Fe-curtain with the recombination Several DIBSs are visible in this last spectrum, notably 5780A (EW ~ 0.63A), 5797A (0.33A), 6613A (0.32A). 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 Data Base