We identify emission lines of post-iron peak elements in very high signal-to-noise spectra of a sample of planetary nebulae. Analysis of lines from ions of Kr and Xe reveals enhancements in most of the PNe, in agreement with the theories of s-process in AGB star. Surprisingly, we did not detect lines from Br even though s-process calculations indicate that it should be produced with Kr at detectable levels.
@article{arxiv.astro-ph/0605181,
title = {Abundances of s-process elements in planetary nebulae: Br, Kr & Xe},
author = {Y. Zhang and R. Williams and E. Pellegrini and K. Cavagnolo and J. A. Baldwin and B. Sharpee and M. Phillips and X. -W. Liu},
journal= {arXiv preprint arXiv:astro-ph/0605181},
year = {2009}
}
Comments
2 pages, 1 figure, to be published in the Proceedings of the IAU Symposium 234: Planetary Nebulae in Our Galaxy and Beyond, eds. M.J. Barlow, R.H. Mendez