CONSISTENCY OF THE METALLICITY DISTRIBUTIONS OF NEARBY F-DWARF, G-DWARF AND K-DWARF

The consistency of the metallicity distributions of F G and K dwarfs i s studied. We present a new metallicity distribution for K dwarfs usin g metallicities determined from uvby photometry. There is a remarkable paucity of metal-poor K dwarfs in analogy with the G dwarf problem. W e show that late-type dwarfs have consistent metallicity distributions . We also propose preliminary corrections to these distributions to ta ke into account the contamination of the uvby indices due to the chrom ospheric activity in these stars, since around 30% of the nearby late- type dwarfs have active chromospheres. We consider the possibility tha t the metallicity distribution of cooler stars may be different from t hat of the hotter stars due to (i) metal-enhanced star formation and ( ii) a metallicity bias in the catalogue of nearby stars. We conclude t hat these hypotheses are unlikely to produce important differences in the metallicity distributions of late-type dwarfs.