Carbon and oxygen in 107 dwarf stars

Oxygen abundances were determined by fits to the 6300.304{AA} OI line, and for the determination of the carbon abundances we used 3 lines of the CI atom and 12 lines of C_2_ molecule for the determination of carbon abundances. We determine masses and abundances of 107 CHEPS stars. There is no evidence that the [C/O] ratio depends on V sin i or the mass of the star, within our constrained range of masses, i.e. 0.82<M*/M_{sun}_<1.5 and metallicities -0.27<[Fe/H]<+0.39 and we confirm that metal-rich dwarf stars with planets are more carbon-rich in comparison with non-planet host stars, with a statistical significance of 96%.

We find tentative evidence that there is a slight offset to lower abundance and a greater dispersion in oxygen abundances relative to carbon, and interpret this as potentially arising from the production of the oxygen being more effective at more metal-poor epochs. We also find evidence that for lower mass star's the angular momentum loss in star's with planets as measured by Vsini is steeper than star's without planets.

In general, we find that the fast rotators (Vsini>5km/s) are massive stars.