HEAVY-ELEMENT DISPERSION IN THE METAL-POOR GLOBULAR CLUSTER M92

Journal Article · Fri Jul 15 04:00:00 EDT 2011 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/142/1/22· OSTI ID:21583058

Roederer, Ian U ^[1]; Sneden, Christopher ^[2]

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1. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
2. Department of Astronomy, University of Texas at Austin, 1 University Station, C1400, Austin, TX 78712 (United States)

Dispersion among the light elements is common in globular clusters (GCs), while dispersion among heavier elements is less common. We present detection of r-process dispersion relative to Fe in 19 red giants of the metal-poor GC M92. Using spectra obtained with the Hydra multi-object spectrograph on the WIYN Telescope at Kitt Peak National Observatory, we derive differential abundances for 21 species of 19 elements. The Fe-group elements, plus Y and Zr, are homogeneous at a level of 0.07-0.16 dex. The heavy-elements La, Eu, and Ho exhibit clear star-to-star dispersion spanning 0.5-0.8 dex. The abundances of these elements are correlated with one another, and we demonstrate that they were produced by r-process nucleosynthesis. This r-process dispersion is not correlated with the dispersion in C, N, or Na in M92, indicating that r-process inhomogeneities were present in the gas throughout star formation. The r-process dispersion is similar to that previously observed in the metal-poor GC M15, but its origin in M15 or M92 is unknown at present.

• OSTI ID: 21583058
• Journal Information: Astronomical Journal (New York, N.Y. Online), Journal Name: Astronomical Journal (New York, N.Y. Online) Journal Issue: 1 Vol. 142; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
ELEMENTS
EVOLUTION
METALS
NUCLEAR REACTIONS
NUCLEOSYNTHESIS
R PROCESS
STAR EVOLUTION
STARS
SYNTHESIS
TELESCOPES