NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Silicon and carbon abundances in the Orion nebulaWe assess the gas-phase abundances of Si and C from our recent measurements of Si(2+), C(2+), and C(+) in the Orion Nebula by expanding on our earlier 'blister' models. The C and Si abundances are derived from new IUE high-dispersion spectra of the C(2+) 1907, 1909 A and Si(2+) 1883, 1892 A lines and archival IUE data. Gas-phase Si/C = 0.016 in the Orion ionized volume and is particularly insensitive to uncertainties in extinction and temperature structure. The solar value is 0.098. Gas-phase C/H = 2.8 x 10 exp -4 and Si/H = 4.5 x 10 exp -6. Compared to solar, Si is depleted by a factor of about 8 in the ionized region, while C is much less depleted (factor of 1.3), if depleted at all. This suggests that most Si resides in dust grains even in the ionized volume. Thus, most of the observed forbidden Si II 34.8-micron emission in Orion does not arise in the H II region.
Document ID
19930068050
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Rubin, Robert H.
(NASA Ames Research Center Moffett Field; Orion Enterprises, Mountain View, CA, United States)
Dufour, Reginald J.
(NASA Ames Research Center Moffett Field, CA, United States)
Walter, Donald K.
(Rice Univ. Houston, TX, United States)
Date Acquired
August 16, 2013
Publication Date
August 10, 1993
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 413
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
93A52047
Funding Number(s)
CONTRACT_GRANT: NCA2-612
CONTRACT_GRANT: NCA2-570
CONTRACT_GRANT: NAG5-262
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available