Issue |
A&A
Volume 395, Number 3, December I 2002
|
|
---|---|---|
Page(s) | 789 - 801 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20021314 | |
Published online | 18 November 2002 |
Evolution of deuterium,
He and
He in the Galaxy
1
Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34131 Trieste, Italia
2
Dipartimento di Astronomia, Universita' degli Studi di Trieste, Via G. B. Tiepolo 11, 34131 Trieste, Italia
Corresponding author: C. Chiappini, chiappini@ts.astro.it
Received:
8
July
2002
Accepted:
5
September
2002
In this work we present the predictions of the “two-infall model” concerning the evolution of D, 3He and 4He in the solar vicinity, as well as their distribution along the Galactic disk. Our results show that, when adopting detailed yields taking into account the extra-mixing process in low and intermediate mass stars, the problem of the overproduction of 3He by the chemical evolution models is solved. The predicted distribution of 3He along the disk is also in agreement with the observations. We also predict
the distributions of D/H, D/O and D/N along the disk, in particular
D abundances close to the primordial value are predicted in the outer regions of the Galaxy. The predicted D/H, D/O and D/N abundances in the local interstellar medium are in agreement with the mean values observed by the Far Ultraviolet Spectroscopic Explorer mission, although a large spread in the D abundance
is present in the data.
Finally, by means of our chemical evolution model, we can constrain the primordial value of the deuterium abundance, and we find a value of (D/H) which implies
0.017, in agreement with the values from the Cosmic Microwave Background radiation analysis. This value in turn implies a primordial 4He abundance
0.244.
Key words: Galaxy: abundances / Galaxy: evolution / Galaxy: formation
© ESO, 2002
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