FLUORINE ABUNDANCES OF GALACTIC LOW-METALLICITY GIANTS

Journal Article · Fri Mar 01 00:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/765/1/51· OSTI ID:22167631

Li, H. N.; Zhao, G. ^[1]; Ludwig, H. -G.; Caffau, E.

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1. Key Lab of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang, Beijing 100012 (China)

With abundances and 2{sigma} upper limits of fluorine (F) in seven metal-poor field giants, nucleosynthesis of stellar F at low metallicity is discussed. The measurements are derived from the HF(1-0) R9 line at 23358 A using near-infrared K-band high-resolution spectra obtained with CRIRES at the Very Large Telescope. The sample reaches lower metallicities than previous studies on F of field giants, ranging from [Fe/H] = -1.56 down to -2.13. Effects of three-dimensional model atmospheres on the derived F and O abundances are quantitatively estimated and shown to be insignificant for the program stars. The observed F yield in the form of [F/O] is compared with two sets of Galactic chemical evolution models, which quantitatively demonstrate the contribution of Type II supernova (SN II) {nu}-process and asymptotic giant branch/Wolf-Rayet stars. It is found that at this low-metallicity region, models cannot well predict the observed distribution of [F/O], while the observations are better fit by models considering an SN II {nu}-process with a neutrino energy of E {sub {nu}} = 3 Multiplication-Sign 10{sup 53} erg. Our sample contains HD 110281, a retrograde orbiting low-{alpha} halo star, showing a similar F evolution as globular clusters. This supports the theory that such halo stars are possibly accreted from dwarf galaxy progenitors of globular clusters in the halo.

• OSTI ID: 22167631
• Journal Information: Astrophysical Journal, Vol. 765, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTRONOMY
ASYMPTOTIC SOLUTIONS
COMPARATIVE EVALUATIONS
COSMIC NEUTRINOS
ELEMENT ABUNDANCE
EMISSION SPECTRA
FLUORINE
GALACTIC EVOLUTION
GALAXIES
HYDROFLUORIC ACID
HYDROGEN
INFRARED SPECTRA
IRON
NUCLEOSYNTHESIS
STAR ACCRETION
STAR CLUSTERS
STELLAR ATMOSPHERES
WOLF-RAYET STARS