NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Diffuse interstellar band formation in dense cloudsData are presented which show that the strengths of the diffuse interstellar bands at 4430, 5780, and 5797 A tend to be deficient with respect to color excess in the lines of sight to stars lying behind dense interstellar clouds. In addition, diffuse-band data for ten stars in the well-studied rho Ophiuchi cloud complex are presented, and systematic variations of band strengths with optical depth are discussed. It is found that the band strength per grain in the line of sight apparently decreases with increasing grain size, taking the ratio of total-to-selective absorption and the wavelength of maximum polarization as indicators of the latter. It is concluded that diffuse-band formation probably takes place most efficiently in the outer regions of interstellar clouds. This may be consistent with a diffuse-band origin in small grains which are coated by mantles in cloud interiors; or in some molecule or molecules which are most abundant in the outer portions of interstellar clouds.
Document ID
19750032692
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Snow, T. P., Jr.
Cohen, J. G.
(Kitt Peak National Observatory Tucson, Ariz., United States)
Date Acquired
August 8, 2013
Publication Date
December 1, 1974
Publication Information
Publication: Astrophysical Journal
Volume: 194
Subject Category
Astrophysics
Accession Number
75A16764
Funding Number(s)
CONTRACT_GRANT: NSF GP-28881
CONTRACT_GRANT: NAS5-1810
Distribution Limits
Public
Copyright
Other

Available Downloads

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