CH Cygni in 2004 - II: Nebular spectrum features

Abstract

We report in a series on the spectra of CH Cygni obtained in October 2004 in this paper. The spectra showed emission lines of H I, [O I], [O III], [N II], [Ne III] and Fe II: most of them became stronger than those obtained in April 2004. In order to retrieve the intrinsic emission profile, we removed the underlying M-type spectrum and telluric lines of O2 from the spectra. Then, we deconvoluted the resulting Hα and [O III] profiles into several Gaussian functions. Radial velocities of all lines observed in October 2004 were measured. Results are compared with those in April 2004, and are discussed by way of an accretion disk and a circumstellar model. © 2007 Elsevier B.V. All rights reserved.