Rubidium in the Interstellar Medium
Abstract
We present high-resolution observations of interstellar rubidium toward ο Per, ζ Per, AE Aur, HD 147889, χ Oph, ζ Oph, and 20 Aql to obtain the 85Rb/87Rb isotope ratio in each direction. Both the stable 85Rb and long-lived 87Rb isotopes are created through the neutron capture s- and r- processes. Theoretical predictions indicate that 85Rb is mainly an r-process nuclide, whereas 87Rb is produced mainly through the s-process. The Rb I line at 7800 Angstroms is the focus of our study on rubidium in diffuse interstellar gas. The 85Rb/87Rb ratio was compared to the Solar System meteoritic ratio of 2.59. The ratio toward HD 147889 is much lower than the meteoritic value, but consistent with the low ratio toward ρ Oph A measured previously. We attribute these results to a deficit of r-processed 85Rb in the Rho Ophiuchus Molecular Cloud. Within the mutual uncertainties, all other lines of sight are consistent with the ratio for the Solar System.
- Publication:
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American Astronomical Society Meeting Abstracts #212
- Pub Date:
- May 2008
- Bibcode:
- 2008AAS...212.0503W