The double sub-giant branch of NGC 6656 (M 22): a chemical characterization

Download
  1. Get@NRC: The double sub-giant branch of NGC 6656 (M 22): a chemical characterization (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1051/0004-6361/201118381
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleAstronomy & Astrophysics
ISSN0004-6361
1432-0746
Volume541
Article numberA15
AbstractWe present an abundance analysis of 101 subgiant branch (SGB) stars in the globular cluster M 22. Using low-resolution FLAMES/GIRAFFE spectra we have determined abundances of the neutron-capture strontium and barium and the light element carbon. With these data we explore relationships between the observed SGB photometric split in this cluster and two stellar groups characterized by different contents of iron, slow neutron-capture process (s-process) elements, and the α element calcium, which we previously discovered in M 22’s red-giant stars. We show that the SGB stars correlate in chemical composition and the color–magnitude diagram position. The stars with higher metallicity and relative s-process abundances define a fainter SGB, while stars with lower metallicity and s-process content reside on a relatively brighter SGB. This result has implications for the relative ages of the two stellar groups of M 22. In particular, it is inconsistent with a broad spread in ages of the two SGBs. By accounting for the chemical content of the two stellar groups, isochrone fitting of the double SGB suggests that their agesare not different by more than ~300 Myr.
Publication date
LanguageEnglish
AffiliationNational Science Infrastructure; National Research Council Canada
Peer reviewedYes
NPARC number21268986
Export citationExport as RIS
Report a correctionReport a correction
Record identifier566d8bb5-a5c3-4288-85a1-c7b68b0a1853
Record created2013-11-29
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)
Date modified: