The Extremely Metal-poor, Neutron Capture-rich Star CS 22892-052: A Comprehensive Abundance Analysis

By C. Sneden, J. Cowan, J. E. Lawler, I. Ivans, S. Burles, Timothy C. Beers, F. Primas, V. Hill, J. Truran, G. Fuller and 2 more. 2003

444 citations recorded by the source corpus.

High-resolution spectra obtained with three ground-based facilities and the Hubble Space Telescope (HST) have been combined to produce a new abundance analysis of CS 22892-052, an extremely metal-poor giant with large relative enhancements of neutron capture elements. A revised model stellar atmosphere has been derived with the aid of a large number of Fe peak transitions, including both neutral and ionized species of six elements. Several elements, including Mo, Lu, Au, Pt, and Pb, have been detected for the first time in CS 22892-052, and significant upper limits have been placed on the abundances of Ga, Ge, Cd, Sn, and U in this star. In total, abundance measurements or upper limits have been determined for 57 elements, far more than previously possible. New Be and Li detections in CS 22892-052 indicate that the abundances of both these elements are significantly depleted compared to unevolved main-sequence turnoff stars of similar metallicity. Abundance comparisons show an excellent agreement between the heaviest n-capture elements (Z ≥ 56) and scaled solar system r-process abundances, confirming earlier results for CS 22892-052 and other metal-poor stars. New theoretical r-process calculations also show good agreement with CS 22892-052 abundances and the solar r-process abundance components. The abundances of lighter elements (40 ≤ Z ≤ 50), however, deviate from the same scaled abundance curves that match the heavier elements, suggesting different synthesis conditions or sites for the low-mass and high-mass ends of the abundance distribution. The detection of Th and the upper limit on the U abundance together imply a lower limit of 10.4 Gyr on the age of CS 22892-052, quite consistent with the Th/Eu age estimate of 12.8± ≃ 3 Gyr. An average of several chronometric ratios yields an age 14.2± ≃ 3 Gyr.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/bbc273e467ced0d8dbca2ce4fd4431ba77f2ffd1

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In Astronomy and Astrophysics

1. B. Metzger
2. Timothy C. Beers
3. C. Sneden
4. Roberto Gallino
5. A. Karakas
6. D. Kasen
7. Martin Asplund
8. A. Frebel

In Instrumentation

1. Timothy C. Beers
2. C. Sneden
3. A. Frebel
4. Roberto Gallino
5. Martin Asplund
6. J. Cowan
7. J. Norris
8. M. Walker

Citations in the corpus

• Nucleosynthesis in the Outflow from Gamma-Ray Burst Accretion Disks (2005, background): “It is interesting to note that both meteoritic data Qian &Wasserburg (1998) and observations of metal poor halo stars, e.g. Sneden et al (2003), suggest two r-process sites.”
• A SEARCH FOR STARS OF VERY LOW METAL ABUNDANCE. VI. DETAILED ABUNDANCES OF 313 METAL-POOR STARS (2014, methodology): “The explanation for this offset is the cumulative effect of several differences between our study and previous ones, and we demonstrate this using the Sneden et al. (2003) analysis of CS 22892–052.”
• Near-Ultraviolet Observations of HD 221170: New Insights into the Nature of r-Process-rich Stars (2006, methodology): “This ratio is virtually identical to that found for CS 22892-052 (−0.62, Sneden et al. 2003), BD+17◦3248 (−0.51, Cowan et al. 2002) and HD 115444 (−0.60, Westin et al. 2000).”
• Abundances in giant stars of the globular cluster NGC 6752 (2005, unknown): “Some halo stars with large enhancements of neutroncapture elements show scaled solar r-process abundance distributions for Ba and heavier elements (e.g., Cowan et al. 1999; Westin et al. 2000; Hill et al. 2002; Sneden et al. 2003).”
• NEW RARE EARTH ELEMENT ABUNDANCE DISTRIBUTIONS FOR THE SUN AND FIVE r-PROCESS-RICH VERY METAL-POOR STARS (2009, background): “Additional descriptions of these stellar spectra can be found in their original studies: BD+17 3248, Cowan et al. (2002); CS 22892-052, Sneden et al. (2003); HD 115444, Westin et al. (2000); HD 221170, Ivans et al. (2006); see also Cowan et al. (2005).”
• The Binary Frequency Among Carbon-enhanced, s-Process-rich, Metal-poor Stars (2004, background): “…29498-043; Aoki et al. 2002d,e and CS 22949-037; Depagne et al. 2002) also appear to exhibit large enhancements in N, O, and the α-elements, while a single case of a highly r-process-enhanced CEMP star, CS 22892-052 (Sneden et al. 2003, and references therein) has been noted (hereafter, CEMP-r).”
• THE s-PROCESS IN ASYMPTOTIC GIANT BRANCH STARS OF LOW METALLICITY AND THE COMPOSITION OF CARBON-ENHANCED METAL-POOR STARS (2011, background): “There are also halo stars with pure r enhancements, so-called rI (usually classified by setting 0.5<[Eu/Fe]<1) and rII ([Eu/Fe]>1), one of which, the famous CS 22892-052 (Sneden et al. 2003), belongs to the CEMP star family.”
• Spectroscopic Studies of Very Metal-poor Stars with the Subaru High Dispersion Spectrograph. III. Light Neutron-Capture Elements (2005, background): “Studies of the detailed abundance patterns of such objects, as has been made for stars with excesses of heavy r-process elements like CS 22892-052 (Sneden et al. 2003) and CS 31082-001 (Hill et al. 2002), will provide a definitive constraint onmodeling the presumed additional process that creates…”
• The elemental composition of the Sun - III. The heavy elements Cu to Th (2014, background): “…are strongly enriched in the r-process elements, with an abundance pattern remarkably similar to the r-process signature in the solar system, suggesting the dominance of some universal process active throughout cosmic time (e.g. Cayrel et al. 2001, Sneden et al. 2003, Frebel et 1 ar X iv :1 40 5.”
• CARBON-ENHANCED METAL-POOR STAR FREQUENCIES IN THE GALAXY: CORRECTIONS FOR THE EFFECT OF EVOLUTIONARY STATUS ON CARBON ABUNDANCES (2014, unknown): “…al. (1995), Meléndez & Barbuy (2002), Placco et al. (2013, 2014b), Preston & Sneden (2001), Preston et al. (2006), Roederer et al. (2008a, 2008b, 2010, 2014), Simmerer et al. (2004), Sivarani et al. (2006), Sneden et al. (2003), Thompson et al. (2008), Yong et al. (2013), and Zhang et al. (2011).”
• The Hamburg/ESO R-process enhanced star survey (HERES). II. Spectroscopic analysis of the survey sample (2005, background): “For CS 22186-025, CS 22892-052, and CS 31082-001, we compare with the studies of Cayrel et al., Sneden et al. (2003), and Hill et al. (2002), respectively.”
• Nucleosynthesis in the Early Galaxy (2007, background): “A few of these stars have been found to date, with CS 22892-052 (Sneden et al. 2003) being the prime example.”
• Spectroscopic Studies of Extremely Metal-Poor Stars with the Subaru High Dispersion Spectrograph. II. The r-Process Elements, Including Thorium (2004, methodology): “…stars and that of the solar system r-process component has already been reported for several very metal-poor stars by previous studies (e.g., Sneden et al. 1996, 2000, 2003b; Westin et al. 2000; Johnson & Bolte 2001; Hill et al. 2002; Cowan et al. 2002), and is sometimes referred to as the…”
• The Hamburg/ESO R-process enhanced star survey (HERES) - III. HE 0338-3945 and the formation of the r + s stars (2006, methodology): “Holmium: The single Ho line at 4152 Å has atomic data including hfs taken from Sneden et al. (2003a).”