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Title: CHARACTERIZING THE HEAVY ELEMENTS IN GLOBULAR CLUSTER M22 AND AN EMPIRICAL s-PROCESS ABUNDANCE DISTRIBUTION DERIVED FROM THE TWO STELLAR GROUPS

Abstract

We present an empirical s-process abundance distribution derived with explicit knowledge of the r-process component in the low-metallicity globular cluster M22. We have obtained high-resolution, high signal-to-noise spectra for six red giants in M22 using the Magellan Inamori Kyocera Echelle spectrograph on the Magellan-Clay Telescope at Las Campanas Observatory. In each star we derive abundances for 44 species of 40 elements, including 24 elements heavier than zinc (Z = 30) produced by neutron-capture reactions. Previous studies determined that three of these stars (the 'r+s group') have an enhancement of s-process material relative to the other three stars (the 'r-only group'). We confirm that the r+s group is moderately enriched in Pb relative to the r-only group. Both groups of stars were born with the same amount of r-process material, but s-process material was also present in the gas from which the r+s group formed. The s-process abundances are inconsistent with predictions for asymptotic giant branch (AGB) stars with M {<=} 3 M{sub Sun} and suggest an origin in more massive AGB stars capable of activating the {sup 22}Ne({alpha},n){sup 25}Mg reaction. We calculate the s-process 'residual' by subtracting the r-process pattern in the r-only group from the abundances in the r+smore » group. In contrast to previous r- and s-process decompositions, this approach makes no assumptions about the r- and s-process distributions in the solar system and provides a unique opportunity to explore s-process yields in a metal-poor environment.« less

Authors:
 [1];  [2];  [3]
  1. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
  2. Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching bei Muenchen (Germany)
  3. Department of Astronomy, University of Texas at Austin, 1 University Station, C1400, Austin, TX 78712 (United States)
Publication Date:
OSTI Identifier:
21612610
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 742; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/742/1/37; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; ASYMPTOTIC SOLUTIONS; DECOMPOSITION; MAGNESIUM 25; NEUTRON REACTIONS; NUCLEOSYNTHESIS; R PROCESS; S PROCESS; SOLAR SYSTEM; STARS; TELESCOPES; ZINC; ALKALINE EARTH ISOTOPES; BARYON REACTIONS; CHEMICAL REACTIONS; ELEMENTS; EVEN-ODD NUCLEI; EVOLUTION; HADRON REACTIONS; ISOTOPES; LIGHT NUCLEI; MAGNESIUM ISOTOPES; MATHEMATICAL SOLUTIONS; METALS; NUCLEAR REACTIONS; NUCLEI; NUCLEON REACTIONS; STABLE ISOTOPES; STAR EVOLUTION; SYNTHESIS

Citation Formats

Roederer, I U, Marino, A F, and Sneden, C. CHARACTERIZING THE HEAVY ELEMENTS IN GLOBULAR CLUSTER M22 AND AN EMPIRICAL s-PROCESS ABUNDANCE DISTRIBUTION DERIVED FROM THE TWO STELLAR GROUPS. United States: N. p., 2011. Web. doi:10.1088/0004-637X/742/1/37; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Roederer, I U, Marino, A F, & Sneden, C. CHARACTERIZING THE HEAVY ELEMENTS IN GLOBULAR CLUSTER M22 AND AN EMPIRICAL s-PROCESS ABUNDANCE DISTRIBUTION DERIVED FROM THE TWO STELLAR GROUPS. United States. https://doi.org/10.1088/0004-637X/742/1/37; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Roederer, I U, Marino, A F, and Sneden, C. 2011. "CHARACTERIZING THE HEAVY ELEMENTS IN GLOBULAR CLUSTER M22 AND AN EMPIRICAL s-PROCESS ABUNDANCE DISTRIBUTION DERIVED FROM THE TWO STELLAR GROUPS". United States. https://doi.org/10.1088/0004-637X/742/1/37; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21612610,
title = {CHARACTERIZING THE HEAVY ELEMENTS IN GLOBULAR CLUSTER M22 AND AN EMPIRICAL s-PROCESS ABUNDANCE DISTRIBUTION DERIVED FROM THE TWO STELLAR GROUPS},
author = {Roederer, I U and Marino, A F and Sneden, C},
abstractNote = {We present an empirical s-process abundance distribution derived with explicit knowledge of the r-process component in the low-metallicity globular cluster M22. We have obtained high-resolution, high signal-to-noise spectra for six red giants in M22 using the Magellan Inamori Kyocera Echelle spectrograph on the Magellan-Clay Telescope at Las Campanas Observatory. In each star we derive abundances for 44 species of 40 elements, including 24 elements heavier than zinc (Z = 30) produced by neutron-capture reactions. Previous studies determined that three of these stars (the 'r+s group') have an enhancement of s-process material relative to the other three stars (the 'r-only group'). We confirm that the r+s group is moderately enriched in Pb relative to the r-only group. Both groups of stars were born with the same amount of r-process material, but s-process material was also present in the gas from which the r+s group formed. The s-process abundances are inconsistent with predictions for asymptotic giant branch (AGB) stars with M {<=} 3 M{sub Sun} and suggest an origin in more massive AGB stars capable of activating the {sup 22}Ne({alpha},n){sup 25}Mg reaction. We calculate the s-process 'residual' by subtracting the r-process pattern in the r-only group from the abundances in the r+s group. In contrast to previous r- and s-process decompositions, this approach makes no assumptions about the r- and s-process distributions in the solar system and provides a unique opportunity to explore s-process yields in a metal-poor environment.},
doi = {10.1088/0004-637X/742/1/37; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
url = {https://www.osti.gov/biblio/21612610}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 742,
place = {United States},
year = {Sun Nov 20 00:00:00 EST 2011},
month = {Sun Nov 20 00:00:00 EST 2011}
}