The recent star formation history of the Hipparcos solar neighbourhood

We use data from the Hipparcos catalogue to construct colour-magnitude diag rams for the solar neighbourhood, which are then treated using advanced Bay esian analysis techniques to derive the star formation rate history, SFR(t) , of this region over the last 3 Gyr. The method we use allows the recovery of the underlying SFR(t) without the need of assuming any a priori structu re or condition on SFR(t), and hence yields a highly objective result. The remarkable accuracy of the data permits the reconstruction of the local SFR (t) with an unprecedented time resolution of approximate to 50 Myr. An SFR( t) that has an oscillatory component of period approximate to 0.5 Gyr is fo und, superimposed on a small level of constant star formation activity. Pro blems arising from the non-uniform selection function of the Hipparcos sate llite are discussed and treated. Detailed statistical tests are then perfor med on the results, which confirm the inferred SFR(t) to be compatible with the observed distribution of stars.