According to the obtained photometry of 
stars brighter than 10 mag in the region
of the Carina Spiral Feature, the young main-sequence objects are concentrated in narrow
intervals of Galactic Longitude at directions 
and 
. The region contains
also individual older stars more uniformly spread over the whole region. The value of the
color excess E(B-V) for the whole field does not exceed 0.54 mag to a distance of 5 kpc.
According to the obtained distances, the observed stars are spread out in depth over more
than 3 kpc. The mean distance for the more obvious concentration of young stars that
appears at is 
pc. The spread one could expect taking into account
the uncertainties in Mv(uvby
) determination is 
260 pc at this distance. The obtained standard deviation is almost 4 time larger that one could expect if the spread of these stars were
not real but due only to errors in distance determination. The 
test applied to these
stars rejects the null hypothesis of normal distribution of the obtained distances at a 99%
level of significance. The extent of this concentration at a right angle to the line of sight is
about 60 pc. It is more likely that these stars belong to a huge stellar complex and are
seen in projection on the line of sight, rather than representing an association born from a single
protostellar cloud. According to this sample, this complex is stretched out over more than 3
kpc, while the thickness in the Galactic radial direction is about 200 pc and the thickness in the
"Z" direction is 300 pc.
According to this sample (Fig. 3), there is a sign of existence an age gradient at the
regions approximately 
and 
. In these regions, the
youngest
stars and the more evolved stars do not have exactly the same spatial distribution - the younger stars
appear to be closer to the inner part of the Carina Arm in comparison to the more evolved stars. This
is more obvious for the field of the Car OB2 complex; for the Car OB1 field the number of the
stars observed is not
sufficient for even preliminary conclusions.
Acknowledgements
I am grateful to Dr. Dave Kilkenny for his help in the observations and data reduction and to Dr. Cameron Reed for the reading of the manuscript and useful comments. Special thanks are due to Dr. William Buscombe for the valuable discussion of the spectral classification of the stars involved here and to Dr. Wilhelm Seggewiss for comments that significantly improved the last version of the paper. This work was supported by National Bulgarian Science Foundation under contract F 619/1996.