High spectral resolution monitoring of Nova V339 Delphini with TIGRE

¹ Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
e-mail: ivan.de.gennaro.aquino@hs.uni-hamburg.de
² Departamento de Astronomía, Universidad de Guanajuato, Apartado Postal 144, 36000 Guanajuato, Mexico
³ Department of Astrophysics, Geophysics and Oceanography, University of Liège, 17 allée du 6 Août, B5c, 4000 Sart Tilman, Belgium

Received: 5 February 2015
Accepted: 7 July 2015

Abstract

Aims. We investigate the early development of the classical nova V339 Del (Nova Delphini 2013) through high-resolution optical spectroscopy. To study the structure of the ejecta, we focus on the evolution of the absorption and emission features and the changes within the line profiles.

Methods. We obtained spectra with the robotic 1.2 m telescope TIGRE equipped with the HEROS spectrograph (R = 20 000, wavelength coverage from 3800 to 8800 Å). Our data set covers the outburst from 3 until 121 days after discovery.

Results. We provide a qualitative analysis of the spectra, describing the line profiles evolution and providing a rich list of identified lines. During the optically thick phase, we detected several blue-shifted absorption features from s-processed elements, whose origin is unclear. The presence of strong lines from C/O and the absence of Neon features confirm that the nature of the central white dwarf is a CO type. The later “nebular” phase spectra show evidence of the non-spherical, inhomogeneous structure of the ejecta. The detailed evolution of the line profiles and appearance of high ionization species (e.g. N III, O III, He II, [Fe VII]) are direct consequences of the re-ionization of the ejecta during the peak of the soft X-ray emission.