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Title: THE TERZAN 5 PUZZLE: DISCOVERY OF A THIRD, METAL-POOR COMPONENT

We report on the discovery of three metal-poor giant stars in Terzan 5, a complex stellar system in the Galactic bulge, known to have two populations at [Fe/H] = –0.25 and +0.3. For these three stars we present new echelle spectra obtained with NIRSPEC at Keck II, which confirm their radial velocity membership and provide an average [Fe/H] = –0.79 dex iron abundance and [α/Fe] = +0.36 dex enhancement. This new population extends the metallicity range of Terzan 5 to 0.5 dex more metal poor, and it has properties consistent with having formed from a gas polluted by core-collapse supernovae.
Authors:
 [1] ; ; ; ; ;  [2] ;  [3]
  1. INAF—Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy)
  2. Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, viale Berti Pichat 6/2, I-40127 Bologna (Italy)
  3. Department of Physics and Astronomy, Physics and Astronomy Building, 430 Portola Plaza, P.O. Box 951547, University of California at Los Angeles, Los Angeles, CA 90095-1547 (United States)
Publication Date:
OSTI Identifier:
22364105
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 779; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; GIANT STARS; GRAVITATIONAL COLLAPSE; HYDROGEN; IRON; METALLICITY; MILKY WAY; RADIAL VELOCITY; STAR CLUSTERS; SUPERNOVAE