TY - JOUR
T1 - The first fluorine abundance determinations in extragalactic asymptotic giant branch carbon stars
AU - Abia, C.
AU - Cunha, K.
AU - Cristallo, S.
AU - De Laverny, P.
AU - Domínguez, I.
AU - Recio-Blanco, A.
AU - Smith, V. V.
AU - Straniero, O.
PY - 2011/8/10
Y1 - 2011/8/10
N2 - Fluorine (19F) abundances (or upper limits) are derived in six extragalactic asymptotic giant branch (AGB) carbon stars from the HF(1-0) R9 line at 2.3358 μm in high-resolution spectra. The stars belong to the Local Group galaxies, Large Magellanic Cloud, Small Magellanic Cloud, and Carina dwarf spheroidal, spanning more than a factor of 50 in metallicity. This is the first study to probe the behavior of F with metallicity in intrinsic extragalactic C-rich AGB stars. Fluorine could be measured only in four of the target stars, showing a wide range in F enhancements. Our F abundance measurements together with those recently derived in Galactic AGB carbon stars show a correlation with the observed carbon and s-element enhancements. The observed correlations, however, display a different dependence on the stellar metallicity with respect to theoretical predictions in low-mass, low-metallicity AGB models. We briefly discuss the possible reasons for this discrepancy. If our findings are confirmed in a larger number of metal-poor AGBs, the issue of F production in AGB stars will need to be revisited.
AB - Fluorine (19F) abundances (or upper limits) are derived in six extragalactic asymptotic giant branch (AGB) carbon stars from the HF(1-0) R9 line at 2.3358 μm in high-resolution spectra. The stars belong to the Local Group galaxies, Large Magellanic Cloud, Small Magellanic Cloud, and Carina dwarf spheroidal, spanning more than a factor of 50 in metallicity. This is the first study to probe the behavior of F with metallicity in intrinsic extragalactic C-rich AGB stars. Fluorine could be measured only in four of the target stars, showing a wide range in F enhancements. Our F abundance measurements together with those recently derived in Galactic AGB carbon stars show a correlation with the observed carbon and s-element enhancements. The observed correlations, however, display a different dependence on the stellar metallicity with respect to theoretical predictions in low-mass, low-metallicity AGB models. We briefly discuss the possible reasons for this discrepancy. If our findings are confirmed in a larger number of metal-poor AGBs, the issue of F production in AGB stars will need to be revisited.
KW - galaxies: individual (LMC, SMC, Carina)
KW - stars: AGB and post-AGB
KW - stars: abundances
KW - stars: carbon
UR - http://www.scopus.com/inward/record.url?scp=80051741400&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80051741400&partnerID=8YFLogxK
U2 - 10.1088/2041-8205/737/1/L8
DO - 10.1088/2041-8205/737/1/L8
M3 - Article
AN - SCOPUS:80051741400
SN - 2041-8205
VL - 737
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
M1 - L8
ER -