We present new optical and near-infrared spectra of WD0137-349 ; a close white dwarf - brown dwarf non-interacting binary system with a period of \approx 114 minutes .
We have confirmed the presence of H \alpha emission and discovered He , Na , Mg , Si , K , Ca , Ti , and Fe emission lines originating from the brown dwarf atmosphere .
This is the first brown dwarf atmosphere to have been observed to exhibit metal emission lines as a direct result of intense irradiation .
The equivalent widths of many of these lines show a significant difference between the day and night sides of the brown dwarf .
This is likely an indication that efficient heat redistribution may not be happening on this object , in agreement with models of hot Jupiter atmospheres .
The H \alpha line strength variation shows a strong phase dependency as does the width .
We have simulated the Ca II emission lines using a model that includes the brown dwarf Roche geometry and limb darkening and we estimate the mass ratio of the system to be 0.135 \pm 0.004 .
We also apply a gas-phase equilibrium code using a prescribed drift-phoenix model to examine how the chemical composition of the brown dwarf upper atmosphere would change given an outward temperature increase , and discuss the possibility that this would induce a chromosphere above the brown dwarf atmosphere .