SIMBAD references

In this paper we examine the star formation history inferred from the Hipparcos color-magnitude diagram (CMD) of field stars in the solar vicinity and check whether the whole galactic disk has formed stars in a similar fashion. We find that the properties of the CMD in question are very local and the underlying star formation history cannot hold for the whole disk. With the expected capability of GAIA we examine how far in space GAIA would be able to sample stars with the same precision of parallaxes as Hipparcos. We find that a minimum coverage of about 2 kpc from the Sun is easily achievable. In such a case the star formation history, derived from the GAIA data, is expected to represent the past star forming activity over the whole galactic disk.