First high resolution ultraviolet (HST/STIS) and supporting optical spectroscopy of V339 Del = Nova Del 2013

ATel #5409; S. N. Shore (Univ. of Pisa, INFN-Pisa); G. J. Schwarz (AAS); K. Alton, D. Antao, E. Barbotin, P. Berardi, T. Blank, T. Bohlsen, F. Boubault, D. Boyd, J. Briol, C. Buil, S. Charbonnel, P. Dubreuil, M. Dubs, J. Edlin, T. de France, A. Favaro, O. Garde, K. Graham, D. Greenan, J. Guarro, T. Hansen, D. Hyde, T. Lemoult, R. Leadbeater, G. Martineau, Y. Buchet, J. P. Masviel, J. Montier, B. Mauclaire, E. Pollmann, J. Ribeiro, B. Schram, O. Thizy, J.-N. Terry, F. Teyssier (contributing participants, ARAS); K. L. Page, J. P. Osborne (Leicester); J-U Ness (ESA); S. Starrfield (ASU); F. M. Walter (SUNY-SB); C. E. Woodward (Minnesota); M. F. Bode (John Moores Univ. Liverpool)
on 22 Sep 2013; 23:24 UT
Distributed as an Instant Email Notice Novae
Credential Certification: S. N. Shore (shore@df.unipi.it)

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V339 Del = Nova Del 2013 was observed with the Space Telescope Imagine Spectrograph (STIS) aboard the Hubble Space Telescope (HST) on 2013 Sept. 18.2 UT from 1140-2888 A using the E140M and G230H gratings at a resolution of ~ 100000. At the time, V ~ 8, shortly after t_3. Continuing spectroscopy was provided by the Astronomical Ring for Access to Spectroscopy (ARAS) at resolutions ranging from 3684 - 7431 A with resolutions ranging from 580 - 11000 with time sequences as short as 10 minutes at resolutions up to 12000. The STIS spectra show that the Fe curtain stage was ending at the time, although strong absorption was still detected throughout the STIS range. Emission was detected on Ly alpha, O I 1302, C II 1335, N II] 2142, C II 2324, and Mg II 2800. The absorption at Ly-alpha is dominated now by the interstellar absorption consistent with the optically derived extinction, indicating that the intrinsic neutral hydrogen column density is now likely below 1E20/cm^2. Strong, saturated P Cyg absorption was present on C II 1335 extending to -2500 km/s, about the same as the velocities measured during the fireball stage (ATel#5282). Although heavily obscured by overlying Fe curtain lines, He II 1640A and N IV 1486A may be present. There are no indications of either O III] 1661,1667A or C III] 1909. As observed in T Pyx during the same stage (Day 23 of outburst), the 1180-900 A metallic line absorption were not saturated. The measured flux (1180-2900A) was 1.7e-8 erg/s/cm^2, corrected E(B-V)=0.2(ATel#5304) the flux as 7.8e-18 erg/s/cm^2. Optical monitoring finds that [N II] 5755 A first appeared around Sept. 8, the N III 4640A feature has been recognized shortly before, and after Sept. 10 the He I 5876, 6678, 7065A transitions were observed. The Na I D lines are now gone and the He I 5876 emission shows the optically thin multi-peaked profile typical of the other transitions, e.g. O I 6300,6364. He II 4686 may be weakly present in the N III blend. The Fe II, e.g. 5018A, no longer show the narrow detached absorption features reported earlier although weak absorption remains on H-gamma at -1000 km/s. Comparing these STIS UV spectra with high resolution IUE spectra of the CO nova OS And 1986 obtained between 12 and 21 days after optical discovery (1986 Dec. 17, 26 respectively) shows a very close agreement such that when independently dereddened, they differ by only a scale factor of A~1.5 in flux, indicating that the distance to V339 Del is about 6 kpc (distance to OS And ~ 5.1 kpc with E(B-V)=0.25+/-0.05, see Schwarz et al. 1997, MNRAS, 284, 669). Further observations are planned with STIS in the coming months and we urge continuing optical and near infrared observations of this remarkable opportunity to capture the history of a CO nova in outburst.

ARAS database for Nova Del 2013