Early spectral evolution of Nova Sagittarii 2004 (V5114 Sagittarii)

¹ Vrije Universiteit Brussel, 2 Pleinlaan, Brussels, Belgium e-mail: aederocl@vub.ac.be
² ESO – European Southern Observatory, Alonso de Cordova 3107, Casilla 91001, Santiago, Chile
³ Department of Astronomy, University of Trieste, via Tiepolo 11, Trieste, Italy
⁴ INAF – Osservatorio Astrofisico di Arcetri, L.go E. Fermi 5, Firenze, Italia
⁵ Kavli Institute for Theoretical Physics, UC Santa Barbara, California, 93106, USA
⁶ Space Telescope Science Institute 3700 San Martin Drive, Baltimore, MD, USA
⁷ Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana, 70803, USA
⁸ Department of Physics and Astronomy, SUNY, Stony Brook, NY, 11794-3800, USA
⁹ Aerospace Corporation, PO Box 92957, Los Angeles, CA 90009-2957, USA
¹⁰ University of California San Diego, 9500 Gilman Dr., La Jolla, CA, USA
¹¹ NASA Langley Research Center, 100 NASA Road, Hampton, VA, USA
¹² Isaac Newton Institute, Casilla 8-9, Correo 9, Santiago, Chile
¹³ Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA, USA

Received: 1 June 2006
Accepted: 28 July 2006

Abstract

Aims.We present optical and near-infrared spectral evolution of the Galactic nova V5114 Sgr (2004) during few months after the outburst.

Methods.We use multi-band photometry and line intensities derived from spectroscopy to put constrains on the distance and the physical conditions of the ejecta of V5114 Sgr.

Results.The nova showed a fast decline ( days) and spectral features of spectroscopic class. It reached M_V = -8.7 ± 0.2 mag at maximum light, from which we derive a distance of 7700 ± 700 kpc and a distance from the galactic plane of about 800 pc. Hydrogen and oxygen mass of the ejecta are measured from emission lines, leading to ~10^-6 and , respectively. We compute the filling factor of the ejecta to be in the range 0.1–10^-3. We found the value of the filling factor to decrease with time. The same is also observed in other novae, then giving support to the idea that nova shells are not homogeneously filled in, rather being the material clumped in relatively higher density blobs less affected by the general expanding motion of the ejecta.