A search and modeling of peculiar narrow transient line components in novae spectra

The formation of peculiar transient narrow emission line components observed in the spectra of a few novae is discussed. We aim to constrain the possible physical sources responsible for those unexpected components that present orbital radial velocity modulations, which were first observed in the post-outburst recombination lines of Nova U Sco 2010. A search for candidates showing similar narrow components is presented. Exploratory photoionization simulations indicate that the forming region cannot be restricted to the Roche Lobe of the primary, but could be located around the outer Lagrangian point L3. Further analysis disfavors an origin at the companion star. In addition, we analyze possible correlations between the presence of the narrow components, the basic nova parameters and the spectral classification in the initial permitted line phase.