Tiny HI Clouds in the Local ISM
arXiv:astro-ph/0409427 · doi:10.1007/978-1-4020-3407-7_58
Abstract
Very sensitive HI absorption spectra (tau RMS about 10^-4 over 1 km/s) toward high latitude QSOs have revealed a population of tiny discrete features in the diffuse ISM with peak tau of 0.1 - 2% and core line-widths corresponding to temperatures as low as 20 K. Imaging detections confirm linear dimensions of a few 1000 AU. We suggest these structures may be formed by the stellar winds of intermediate mass stars. A more speculative origin might involve molecular "dark matter".
6 pages, 8 figures, to appear in "The IMF at 50", eds. E. Corbelli, F. Palla, and H. Zinnecker, ASSL (Kluwer)