The Amount of Interstellar Carbon Locked in Solid Hydrogenated Amorphous Carbon
Author(s) -
Douglas G. Furton,
John W. Laiho,
Adolf N. Witt
Publication year - 1999
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/308016
Subject(s) - amorphous carbon , interstellar medium , carbon fibers , absorption (acoustics) , astrophysics , hydrogen , analytical chemistry (journal) , materials science , physics , amorphous solid , chemistry , galaxy , optics , environmental chemistry , crystallography , organic chemistry , composite number , composite material
We review the literature and present new experimental data to determine theamount of carbon likely to be locked in form of solid hydrogenated amorphouscarbon (HAC) grains. We conclude on the basis of a thorough analysis of theintrinsic strength of the C-H stretching band at 3.4 micron that between 10 and80 ppM H of carbon is in the form of HAC grains. We show that it is necessaryto know the level of hydrogenation (H/C) of the interstellar HAC to determinemore precisely the amount of carbon it ties up. We present optical constants,photoluminescence spectroscopy, and IR absorption spectroscopy for a particularHAC sample that is shown to have a 3.4 micron absorption feature that isquantatively consistent with that observed in the diffuse interstellar medium.Comment: This paper is 14 pages long with 5 figures and will appear in the 1 December 1999 issue of Ap
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