Article (Scientific journals)
Abundance correlations in mildly metal-poor stars
Jehin, Emmanuel; Magain, Pierre; Neuforge, Corinne et al.
1999In Astronomy and Astrophysics, 341, p. 241-255
Peer Reviewed verified by ORBi
 

Files


Full Text
Jehin_1999_AA341_241.pdf
Publisher postprint (310.14 kB)
Download

The authors thank EDP sciences for their deposit authorization


All documents in ORBi are protected by a user license.

Send to



Details



Keywords :
STARS: ABUNDANCES; STARS: POPULATION II; NUCLEAR REACTIONS; NUCLEOSYNTHESIS; ABUNDANCES; GALAXY: EVOLUTION
Abstract :
[en] Accurate relative abundances have been obtained for a sample of 21 mildly metal-poor stars from the analysis of high resolution and high signal-to-noise spectra. In order to reach the highest coherence and internal precision, lines with similar dependency on the stellar atmospheric parameters were selected, and the analysis was carried out in a strictly differential way within the sample. With these accurate results, correlations between relative abundances have been searched for, with a special emphasis on the neutron capture elements. This analysis shows that the r elements are closely correlated to the alpha elements, which is in agreement with the generally accepted idea that the r-process takes place during the explosion of massive stars. The situation is more complex as far as the s elements are concerned. Their relation with the alpha elements is not linear. In a first group of stars, the relative abundance of the s elements increases only slightly with the alpha elements overabundance until the latter reaches a maximum value. For the second group, the s elements show a rather large range of enhancement and a constant (and maximum) value of the alpha elements overabundance. This peculiar behaviour leads us to distinguish between two sub-populations of metal-poor stars, namely Pop IIa (first group) and Pop IIb (second group). We suggest a scenario of formation of metal-poor stars based on two distinct phases of chemical enrichment, a first phase essentially consisting in supernova explosions of massive stars, and a second phase where the enrichment is provided by stellar winds from intermediate mass stars. More specifically, we assume that all thick disk and field halo stars were born in globular clusters, from which they escaped, either during an early disruption of the cluster (Pop IIa) or, later, through an evaporation process (Pop IIb). Based on observations obtained at the European Southern Observatory, La Silla, Chile.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Jehin, Emmanuel  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Magain, Pierre  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Neuforge, Corinne
Noels-Grötsch, Arlette ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Parmentier, Geneviève ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Thoul, Anne  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Evol. et stabilité des étoiles et des amas d'étoiles (ESEA)
Language :
English
Title :
Abundance correlations in mildly metal-poor stars
Publication date :
01 January 1999
Journal title :
Astronomy and Astrophysics
ISSN :
0004-6361
eISSN :
1432-0746
Publisher :
EDP Sciences, Les Ulis, France
Volume :
341
Pages :
241-255
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 18 February 2010

Statistics


Number of views
41 (2 by ULiège)
Number of downloads
100 (1 by ULiège)

Scopus citations®
 
52
Scopus citations®
without self-citations
44

Bibliography


Similar publications



Contact ORBi