Context :

Aims : We aim to refine the dynamical masses of the individual component of the low-mass pre-main sequence binary Haro 1-14C .

Methods : We combine the data of the preliminary orbit presented previously with new interferometric observations obtained with the four 8m telescopes of the Very Large Telescope Interferometer .

Results : The derived masses are M _ { a } = 0.905 \pm 0.043 \mathrm { M _ { \sun } } and M _ { b } = 0.308 \pm 0.011 \mathrm { M _ { \sun } } for the primary and secondary components , respectively .
This is about five times better than the uncertainties of the preliminary orbit .
Moreover , the possibility of larger masses is now securely discarded .
The new dynamical distance , d = 96 \pm 9 pc , is smaller than the distance to the Ophiuchus core with a significance of 2.6 \sigma .
Fitting the spectral energy distribution yields apparent diameters of \phi _ { a } = 0.13 \pm 0.01 \mathrm { mas } and \phi _ { b } = 0.10 \pm 0.01 \mathrm { mas } ( corresponding to R _ { \mathrm { a } } = 1.50 \mathrm { R _ { \sun } } and R _ { \mathrm { b } } = 1.13 \mathrm { R _ { \sun } } ) and a visual extinction of A _ { v } \approx 1.75 .
Although the revised orbit has a nearly edge-on geometry , the system is unlikely to be a long-period eclipsing binary .

Conclusions : The secondary in Haro 1-14C is one of the few low-mass , pre-main sequence stars with an accurately determined dynamical mass and distance .