Volume 481, Number 3, April III 2008
|Page(s)||691 - 699|
|Section||Galactic structure, stellar clusters, and populations|
|Published online||07 February 2008|
An inhomogeneous model for the Galactic halo: a possible explanation for the spread observed in s- and r-process elements
Dipartimento di Astronomia, Universitá di Trieste, via G.B. Tiepolo 11, 34131 Trieste, Italy e-mail: email@example.com
Accepted: 14 January 2008
Aims. We propose an explanation for the considerable scatter of the abundances of neutron capture elements observed in low-metallicity stars in the solar vicinity, compared to the small star-to-star scatter observed for the α-elements.
Methods. We have developed a stochastic chemical evolution model in which the main assumption is a random formation of new stars subject to the condition that the cumulative mass distribution follows a given initial mass function.
Results. With our model, we are able to reproduce the different spreads of neutron capture elements and α-elements in low-metallicity stars.
Conclusions. The reason for different observed spreads in neutron capture elements and α-elements resides in the random birth of stars, coupled with different stellar mass ranges, from which α-elements and neutron capture elements originate. In particular, the site of production of α-elements is the whole range of massive stars, from 10 to 80 whereas the mass range of production for neutron capture elements lies between 12 and 30 .
Key words: Galaxy: halo / Galaxy: evolution / stars: abundances / nuclear reactions, nucleosynthesis, abundances
© ESO, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.