Context :

Aims : We have observed the deuterated gas in the high-mass star formation region IRAS 05345+3157 at high-angular resolution , in order to determine the morphology and the nature of such gas .

Methods : We have mapped the N _ { 2 } H ^ { + } ( 1–0 ) line with the Plateau de Bure Interferometer , and the N _ { 2 } D ^ { + } ( 3–2 ) and N _ { 2 } H ^ { + } ( 3–2 ) lines with the Submillimeter Array .

Results : We have detected two condensations in N _ { 2 } D ^ { + } , with masses of \sim 2 - 3 and \sim 9 M _ { \odot } and diameters of 0.05 and 0.09 pc , respectively .
The high deuterium fractionation ( \sim 0.1 ) and the line parameters of the N _ { 2 } D ^ { + } condensations indicate that they are likely low- to intermediate-mass pre–stellar cores , even though other scenarios are possible .

Conclusions :