The Stellar Commodity Market: Cu, Ag, And Au In The Sun And Solar-type Stars
Abstract
The elements copper, silver and gold occupy the same column of the periodic table and share the property that their only stable isotopes are odd-numbered, which implies a need for hyperfine structure data when analyzing their spectral lines. A comparison of their solar photospheric abundances with the standard meteoritic element abundances shows that for two of them (Ag, Au) the differences are as large as or larger than the sum of the uncertainties. With some exceptions, the study of the chemical composition of most stars stops at the end of the iron group of elements. Heavier elements are typically not analyzed, often due to the lack of accurate atomic line data. While the post iron-group elements make a small contribution to the total abundance one can argue that, for many reasons, life on earth would not be the same without copper, silver and gold.
We first revisit the abundances of these elements in the solar photosphere, accounting for the revisions in atomic data since these elements were last analyzed in the photosphere. The hyperfine structure of Cu I and Ag I is included in our synthetic spectrum calculations. The spectra Cu I and Cu II are of current interest to us for the determination of hfs constants based on our new laboratory Fourier transform spectrometer data. We then determine the abundances for these elements in the high-resolution spectra for a sample of solar-like stars, obtained from on-line data bases, using synthetic spectrum techniques. The analysis aims to determine the abundance dispersion of these elements in solar-like stars in the solar neighborhood. Some of these stars are known to possess exo-planets, and the abundances of these elements will be correlated with host star metallicity. In general, we aim to encourage a more extensive use of the periodic table for stellar astrophysics.- Publication:
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American Astronomical Society Meeting Abstracts #215
- Pub Date:
- January 2010
- Bibcode:
- 2010AAS...21542705W