Consistency of the metallicity distributions of nearby F, G and K dwarfs

Abstract

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