High-precision abundances of elements in solar twin stars: Trends with stellar age and elemental condensation temperature

摘要: HARPS spectra with S/N > 600 for 21 solar twin stars are used to determine very precise (sigma ~ 0.01 dex) differential abundances of C, O, Na, Mg, Al, Si, S, Ca, Ti, Cr, Fe, Ni, Zn, and Y in order see how well [X/Fe] is correlated elemental condensation temperature, Tc. In addition, < 0.8 Gyr) stellar ages obtained by interpolating between Yonsei-Yale isochrones the logg - Teff diagram. It confirmed that ratio refractory volatile elements lower Sun than most twins, but many stars, relation Tc not defined. For several there is, instead, an astonishingly tight correlation age amplitudes up 0.2 dex over interval 8 Gyr contrast lack [Fe/H] age. While [Mg/Fe] increases age, s-process element yttrium shows opposite behavior so [Y/Mg] can be as a sensitive chronometer Galactic evolution. [Na/Fe] [Ni/Fe] define Ni-Na similar previously found more metal-poor stars. These results provide new constraints on supernovae yields Furthermore, it C/O evolves little time, which interest discussions composition exoplanets.