Volume 487, Number 1, August III 2008
|Page(s)||307 - 315|
|Published online||04 June 2008|
The neon content of nearby B-type stars and its implications for the solar model problem *,**
Institut d'Astrophysique et de Géophysique, Université de Liège, Allée du 6 août, Bât. B5c, 4000 Liège, Belgium e-mail: firstname.lastname@example.org
2 Katholieke Universiteit Leuven, Departement Natuurkunde en Sterrenkunde, Instituut voor Sterrenkunde, Celestijnenlaan 200D, 3001 Leuven, Belgium
3 Universitäts-Sternwarte München, Scheinerstrasse 1, 81679 München, Germany
Accepted: 28 May 2008
The recent downward revision of the solar photospheric abundances now leads to severe inconsistencies between the theoretical predictions for the internal structure of the Sun and the results of helioseismology. There have been claims that the solar neon abundance may be underestimated and that an increase in this poorly-known quantity could alleviate (or even completely solve) this problem. Early-type stars in the solar neighbourhood are well-suited to testing this hypothesis because they are the only stellar objects whose absolute neon abundance can be derived from the direct analysis of photospheric lines. Here we present a fully homogeneous NLTE abundance study of the optical Ne I and Ne II lines in a sample of 18 nearby, early B-type stars, which suggests log ϵ(Ne) = 7.97 ± 0.07 dex (on the scale in which log ϵ[H] = 12) for the present-day neon abundance of the local interstellar medium (ISM). Chemical evolution models of the Galaxy only predict a very small enrichment of the nearby interstellar gas in neon over the past 4.6 Gyr, implying that our estimate should be representative of the Sun at birth. Although higher by about 35% than the new recommended solar abundance, such a value appears insufficient by itself to restore the past agreement between the solar models and the helioseismological constraints.
Key words: stars: early-type / stars: fundamental parameters / stars: abundances / stars: atmospheres / Sun: helioseismology
© 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.