In this paper we present and analyze new CCD UBVRI photometry
down to V ~ 21 in the region of the
young open cluster Trumpler~15, located in the Carina spiral feature.
The cluster is rather compact and has a core radius of about 2', which translates
in about 1 pc at the distance of the cluster.
We provide the first CCD investigation and update its fundamental parameters.
We identify 90 candidate photometric members on the base of the position in
the color-color and color-magnitude diagrams.
This sample allows us to obtain
a distance of 2.4 ± 0.3 kpc from the Sun and a reddening
E(B-V) = 0.52 ± 0.07.
We confirm that the cluster is young, and fix
a upper limit of 6 million yrs to its age .
In addition, we draw the attention on the lower part of the Main
Sequence (MS) suggesting that some stars can be in contracting phase and
on a gap in the MS, that we show to be a real feature,
the B1-B5 gap found in other young open clusters.
We finally study in details the extinction toward Trumpler 15 concluding
that it is normal and suggesting a value of 2.89 ± 0.
19 for the ratio of total to selective absorption RV.