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The application to main-sequence stars of the rotation-induced mixing theory in the presence of mu-gradients leads to partial mixing in the lithium destruction region, not visible in the atmosphere. The induced lithium depletion becomes visible in the sub-giant phase as soon as the convective zone deepens enough. This may explain why the observed lithium dilution is smoother and the final dilution factor larger than obtained in standard models, while the lithium abundance variations are very small on the main sequence.
We present a survey of lithium abundances in 185 main- sequence field stars with Teff between 5600 and 6600 K and [Fe/H] from -1.4 to +0.2 based on high-resolution spectra of 130 stars and a reanalysis of data from Lambert et al. (1991). The survey t
Beryllium and oxygen abundances have been derived in a sample of F-type field stars for which lithium abundances had been measured previously, with the aim of obtaining observational constraints to discriminate between the different mixing mechanisms
We present new UVES spectra of a sample of 15 cool unevolved stars with and without detected planetary companions. Together with previous determinations, we study Be depletion and possible differences in Be abundances between both groups of stars. We
In an attempt to carry out a systematic study on the behavior of the photospheric abundances of Li, C, and O (along with Fe) for Hyades main-sequence stars in the T_eff range of ~5000-7000K, we conducted an extensive spectrum-synthesis analysis appli
From sector 1--40 {em TESS} observations, 20 new roAp stars, 97 ostensibly non-peculiar stars with roAp-like frequencies (the roA variables) and 617 $delta$~Scuti stars with independent frequencies typical of roAp stars were found. There is no criter