  The triple stellar system delta Vel (composed of two A-type and one F-type
main sequence stars) is particularly interesting as it contains one of the
nearest and brightest eclipsing binaries. It therefore presents a unique
opportunity to determine independently the physical properties of the three
components of the system, as well as its distance. We aim at determining the
fundamental parameters (masses, radii, luminosities, rotational velocities) of
the three components of delta Vel, as well as the parallax of the system,
independently from the existing Hipparcos} measurement. We determined dynamical
masses from high-precision astrometry of the orbits of Aab-B and Aa-Ab using
adaptive optics (VLT/NACO) and optical interferometry (VLTI/AMBER). The main
component is an eclipsing binary composed of two early A-type stars in rapid
rotation. We modeled the photometric and radial velocity measurements of the
eclipsing pair Aa-Ab using a self consistent method based on physical
parameters (mass, radius, luminosity, rotational velocity). From our
self-consistent modeling of the primary and secondary components of the delta
Vel A eclipsing pair, we derive their fundamental parameters with a typical
accuracy of 1%. We find that they have similar masses, respectively
2.43+/-0.02Msol and 2.27+/-0.02Msol. The physical parameters of the tertiary
component (delta Vel B) are also estimated, although to a lower accuracy. We
obtain a parallax of 39.8+/-0.4mas for the system, in satisfactory agreement
(-1.2 sigma) with the Hipparcos value (40.5+/-0.4mas). The physical parameters
we derive represent a consistent set of constraints for the evolutionary
modeling of this system. The agreement of the parallax we measure with the
Hipparcos value to a 1% accuracy is also an interesting confirmation of the
true accuracy of these two independent measurements.
