Solid hydrogen coated graphite particles may be expelled from regions of
star -formation into the general interstellar medium. The solid para- hydrogen
mantles, which contain a small proportion of orthomolecules are stable against
evaporation in the general interstellar radiation field. They are also stable
against physical and chemical sputtering in HI regions. Extinction efficiencies
are calculated for solid hydrogen particles and for graphite particles
with solid hydrogen mantles. Graphite core -solid hydrogen grains are capable
of producing excellent agreement with the interstellar extinction observations
from 2u - 1100 A. The graphite core radius may be in the range ro = 0.04 -
0.06u and the solid hydrogen mantle radius in the range r = 0.15 - 0.25u. The
albedo and phase function of these particles are consistent with the requirements
imposed by the diffuse galactic light. Solid hydrogen is strongly
anisotropic in its crystal structure and optical properties. Approximate
models yield good agreement with the observed trends of the wavelength
dependence of interstellar polarisation.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/623833 |
| Date | 11 1900 |
| Creators | Wickramasinghe, N. C., Krishna Swamy, K. S. |
| Contributors | Univ Arizona, Steward Observ |
| Publisher | Steward Observatory, The University of Arizona (Tucson, Arizona) |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Article |
| Source | Steward Observatory Parker Library SO QB 4 .S752 ARCH |
| Rights | Copyright © All Rights Reserved. |
| Relation | Preprints of the Steward Observatory #15 |
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