In Fig. 1 (click here) we present the two color diagram of the observed stars. The encircled-cross sign refers to the primaries, while the simple-cross refers to the secondaries. The lengths of the cross lines correspond to the accuracy of the results. The curves which are also present refer to the Keenan-Morgan spectral classification for dwarf, giant and supergiant F and G - type stars. As it can be easily seen, both components of most systems are G-type main sequence stars.
In Table 3 (click here) we present the angular separation as well as the
magnitude and colour differences between the two components
of each system. In
eight cases (Nos. 6, 7, 13, 14, 20, 28, 32 and 34), the 
color
index is of the order of some millimagnitudes. Since the accuracy of
the photometric results is of the order of a hundredth of a magnitude
(Table 2) we can practically assume that the components of these eight
systems have the same effective temperature. In almost all cases
(system No. 13 is excluded) 
is much less than one
magnitude, while the angular separation of the components is less than
six arcseconds. By taking under consideration the Aitken limit as
well, we conclude that these seven systems are physical pairs and not
just optical pairs.
In the case of system ``
" both components must be of B-
type. Due to the interstellar reddening, however, their position in
the two color diagram was shifted downwards. This is the reason for
which two points with very negative (U-B) indices are present in the
two color diagram.
From the results obtained from the 40 binaries presented here, it is not possible to derive a good estimation of the width of the main sequence, for the G-type stars. This will be the main goal of our forthcoming activities.
Acknowledgements
This research was mainly carried out in the framework of the project ``Service Centres and Research Networks", initiated and financed by the Belgian Federal Scientific Services (DWTC/SSTC).