Interstellar Iron and Silicon Depletions in Translucent Sight Lines
| Autor: | David M. Meyer, Stefan I. B. Cartledge, Adam A. Miller, Ulysses J. Sofia, James T. Lauroesch |
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| Rok vydání: | 2007 |
| Předmět: |
Physics
education.field_of_study Silicon Astrophysics (astro-ph) Population Extinction (astronomy) FOS: Physical sciences chemistry.chemical_element Astronomy and Astrophysics Astrophysics Silicate chemistry.chemical_compound chemistry Space and Planetary Science education Absorption (electromagnetic radiation) Chemical composition Space Telescope Imaging Spectrograph Line (formation) |
| Zdroj: | The Astrophysical Journal. 659:441-446 |
| ISSN: | 1538-4357 0004-637X |
| DOI: | 10.1086/512178 |
| Popis: | We report interstellar FeII and SiII column densities toward six translucent sight lines (A_V >~ 1) observed with the Space Telescope Imaging Spectrograph (STIS). The abundances were determined from the absorption of SiII] at 2335 Angstroms, and several weak Fe transitions including the first reported detections of the 2234 Angstrom line. We derive an empirical f-value for the FeII 2234 Angstrom transition of log(f lambda) = -1.54 +/- 0.05. The observed sight lines sample a variety of extinction characteristics as indicated by their R_V values, which range from 2.6 - 5.8. The dust-phase abundances of both Si and Fe are positively correlated with the small-grain population (effective radii smaller than a few hundred micron) toward the targets. The physical conditions along the sight lines suggest that this relationship may be due to differences in the survival of small particles in some interstellar environments. The chemical composition of the small grains could either resemble dust mantles or be silicate rich. accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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