Analysis of the carbon-rich very metal-poor dwarf G77-61

Abstract

We present an analysis of the carbon dwarf G77-61, a known binary, based on high resolution Keck spectra. G77-61 has a very-low metallicity, although not as extreme as what was previously conjectured. This star is very carbon-enhanced, the spectra showing very strong CH, CN, and C${}_2$ bands of both ${}^{13}$C and ${}^{12}$C isotopes. Atomic lines are sparse, and often blended, but we were able to derive abundances for Na, Mg, Ca, Cr, Mn, and Fe. Its [Fe/H] of -4.03$\pm$0.1 places it among the lowest metallicity stars known, and its very high [C/Fe]=+2.6, and [N/Fe]=+2.6 among the most C and N-rich metal-poor stars. The carbon isotopic ratio is ${}^{12}$C/${}^{13}C=5\pm$1. No overabundance of s- or r-process elements is detectable, but the upper limits that can be set on these overabundances are not very constraining.

arXiv comment17 pages, 6 figures, accepted by A&A

References in corpus (25)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy
• Color Transformations for the 2MASS Second Incremental Data Release
• Line formation in solar granulation: IV. [O I], OI and OH lines and the photospheric O abundance
• A stellar relic from the early Milky Way
• The extreme r-element rich, iron-poor halo giant CS31082-001: Implications for the r-process site(s) and radioactive cosmochronology
• A Reappraisal of the Solar Photospheric C/O Ratio
• First-generation black-hole-forming supernovae and the metal abundance pattern of a very iron-poor star
• The YY Isochrones for alpha-element Enhanced Mixtures
• The Y^2 Stellar Evolutionary Tracks
• Improved Color-Temperature Relations and Bolometric Corrections for Cool Stars
• Extremely Metal-Poor Stars. VIII. High-Resolution, High-Signal-To-Noise Analysis of Five Stars with [Fe/H] < -3.5
• HE0107-5240, A Chemically Ancient Star.I. A Detailed Abundance Analysis
• A Subaru/HDS study of Lead (Pb) abundances in eight s-process-element-rich, metal-poor stars
• First Stars II. Elemental abundances in the extremely metal-poor star CS 22949--037: A diagnostic of early massive supernovae
• Evolution and Yields of Extremely Metal Poor Intermediate Mass Stars
• Stellar Archaeology: a Keck Pilot Program on Extremely Metal- Poor Stars From the Hamburg/ESO Survey. III. The Lead (Pb) Star HE 0024-2523
• More lead stars
• First stars IV.CS 29497-030: Evidence for operation of the s-process at very low metallicity
• Chemical Composition of the Carbon-rich, Extremely Metal-Poor Star CS 29498--043: A New Class of Extremely Metal-Poor Stars with Excesses of Magnesium and Silicon
• On the oxygen abundance of HE0107-5240
• Oxygen Overabundance in the Extremely Iron-Poor Star CS29498-043
• Relics of subluminous supernovae in metal-poor stars
• The effect of the electron donor H3+ on the pre-main and Main Sequence evolution of low mass zero metallicity stars
• Astrometry and Photometry for Two Dwarf Carbon Stars

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