Bibcode
Santos, N. C.; Israelian, G.; Randich, S.; García López, R. J.; Rebolo, R.
Bibliographical reference
Astronomy and Astrophysics, v.425, p.1013-1027 (2004)
Advertised on:
10
2004
Journal
Citations
28
Refereed citations
25
Description
We present a study of beryllium (Be) abundances in a large sample of
field solar-type dwarfs and sub-giants spanning a large range of
effective temperatures. The Be abundances, computed using a very uniform
set of stellar parameters and near-UV spectra obtained with 3 different
instruments, are used to study the depletion of this light element. The
analysis shows that Be is severely depleted for F stars, as expected by
the light-element depletion models. However, we also show that beryllium
abundances decrease with decreasing temperature for stars cooler than
˜6000 K, a result that cannot be explained by current theoretical
models including rotational mixing, but that is, at least in part,
expected from the models that take into account internal wave physics.
In particular, the light element abundances of the coolest and youngest
stars in our sample suggest that Be, as well as lithium (Li), has
already been burned early during their evolution. Furthermore, we find
strong evidence for the existence of a Be-gap for solar-temperature
stars. The analysis of Li and Be abundances in the sub-giants of our
sample also shows the presence of one case that has still detectable
amounts of Li, while Be is severely depleted. Finally, we compare the
derived Be abundances with Li abundances derived using the same set of
stellar parameters. This gives us the possibility to explore the
temperatures for which the onset of Li and Be depletion occurs.
Based on observations collected with the VLT/UT2 Kueyen telescope
(Paranal Observatory, ESO, Chile) using the UVES spectrograph (Observing
runs 66.C-0116 A, 66.D-0284 A, and 68.C-0058 A), and with the William
Herschel and Nordic Optical Telescopes, operated at the island of La
Palma by the Isaac Newton Group and jointly by Denmark, Finland,
Iceland, and Norway, respectively, in the Spanish Observatorio del Roque
de los Muchachos of the Instituto de Astrofísica de Canarias.