Early spectral evolution of Nova Sgr 2004 (V5114 Sgr)

We present optical and near-infrared spectral evolution of the Galactic
nova V5114 Sgr (2004) during few months after the outburst. 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. The nova showed a fast decline (t_2 \simeq 11 days) and
spectral features of FeII spectroscopic class. It reached M_V = 8.7 \pm
0.2 mag at maximum light, from which we derive a distance of 7700 \pm
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 10^{-7} M_\odot, 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.