Hydrogenated amorphous carbon grains and the 2175 Å interstellar hump

The first extinction spectra of carbon grains condensed in a hydrogen atmosphere are presented to simulate the formation of dust particles in hydrogen-rich astrophysical environments. In order to assess the influence of hydrogen during grain formation unambiguously, experiments were performed in hyd...

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Bibliographic Details
Published inThe Astrophysical journal Vol. 382; no. 2; pp. L97 - L99
Main Authors BLANCO, A, BUSSOLETTI, E, COLANGELI, L, FONTI, S, STEPHENS, J. R
Format Journal Article
LanguageEnglish
Published Chicago, IL University of Chicago Press 01.12.1991
Subjects
661300 - Other Aspects of Physical Science- (1992-)
AMORPHOUS STATE
Astronomy
CARBON
CHEMISTRY
CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
COSMOCHEMISTRY
Earth, ocean, space
ELEMENTS
Exact sciences and technology
HYDROGEN
INTERSTELLAR GRAINS
Interstellar medium (ism) and nebulae in milky way
INTERSTELLAR SPACE
NONMETALS
OPTICAL PROPERTIES
PARTICLES
PHYSICAL PROPERTIES
SPACE
SPECTRA
Stellar systems. Galactic and extragalactic objects and systems. The universe
ULTRAVIOLET SPECTRA
Laboratory study
Interstellar extinction
Hydrogen Molecules
Physical simulation
Ultraviolet spectrum
Argon
Experimental study
Interstellar grain
Hydrogenated amorphous carbon
Carbon
Interstellar matter
Absorption spectrum
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Summary:The first extinction spectra of carbon grains condensed in a hydrogen atmosphere are presented to simulate the formation of dust particles in hydrogen-rich astrophysical environments. In order to assess the influence of hydrogen during grain formation unambiguously, experiments were performed in hydrogen-poor (Ar) and hydrogen-rich (H2) atmospheres allowing the carbon vapor to condense homogeneously into grains. The experimental data confirm the theoretical predictions on the lack of any feature in the UV spectra of fully hydrogenated amorphous carbon grains and clearly show the relevance of the different atmospheres during the condensation process. The results support the idea that grains observed in the interstellar medium, which show a strong 2175-A feature, have undergone some processing subsequent to their formation. 16 refs.
ISSN:0004-637X
1538-4357
DOI:10.1086/186221