Bibcode
Abia, C.; Boffin, H. M. J.; Isern, J.; Rebolo, R.
Referencia bibliográfica
Astronomy and Astrophysics, Vol.272, NO. 2/MAYII, P. 455, 1993
Fecha de publicación:
5
1993
Revista
Número de citas
55
Número de citas referidas
44
Descripción
Lithium abundances, or upper limits, have been derived for 161 galactic
carbon stars, selected from the Two Micron Sky Survey, using high
resolution, high signal to noise ratio spectra and synthetic spectrum
fitting. Fourteen of these C-stars present surface lithium abundances
[log ɛ(Li) ≥ 1.0] higher than theoretically expected during
the AGB phase, but only three are super-rich lithium stars [log
ɛ(Li) >4], which confirms the scarce number of galactic
C-stars (˜2%) of this type. The average masses of the sample stars
suggests the plume mixing, instead of the hot bottom burning mechanism,
as the nucleosynthetic scenario for the production of lithium in these
stars. However, the expected theoretical correlations among lithium
abundances and 12C/13C, C/O ratios do not show up.
The lithium abundance distribution of the remaining stars shows a
pronounced peak at log ɛ(Li) ≍ -0.5 suggesting, when
compared to those in M and SC stars, that no important lithium depletion
occurs during the transition from M to C-star.