Rubidium abundances of galactic disk stars

Spectroscopic determinations of Rubidium abundances were conducted by applying the spectrum fitting method to Rb I 7800 line for an extensive sample ~500 late-type dwarfs as well giants (including Hyades cluster stars) belonging galactic disk population, with aim establishing behaviour [Rb/Fe] ratio stars in metallicity range -0.6<[Fe/H]<+0.3. An inspection resulting revealed that they show a systematic Teff-dependent trend at >5500K; this means results mid-G F Sun) are not reliable (i.e., more or less overestimated), which might be due some imperfect treatment surface convection classical model atmospheres. As such, it was decided confine only late-G and K Teff<5500K adopt solar-system (meteoritic) value reference abundance. The vs.[Fe/H] relations derived field turned out consistent each other, showing gradual increase decrease [Fe/H] (with d[Rb/Fe]/d[Fe/H] gradient ~-0.4 around solar metallicity), is favourably compared theoretical prediction chemical evolution models. Accordingly, study could confirm anomalous (tending subsolar but steeply increasing toward supersolar metallicity) recently reported M dwarf -0.3<[Fe/H]<+0.3.