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Diffuse interstellar band formation in dense clouds

Snow, Theodore P., Jr. and Cohen, Judith G. (1974) Diffuse interstellar band formation in dense clouds. Astrophysical Journal, 194 . pp. 313-322. ISSN 0004-637X. doi:10.1086/153247.

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Data 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.

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Cohen, Judith G.0000-0002-8039-4673
Additional Information:© American Astronomical Society • Provided by the NASA Astrophysics Data System. Received 1974 May 20. The authors wish to acknowledge the kind assistance of Dr. S. Strom, who provided diffuse-band data on five stars, and Dr. G. Wallerstein, who provided plates of some of the p Oph cloud stars. One of us (T. P. S.) carried out a portion of this study while he was a Predoctoral Research Associate at the University of Washington, where his research was supported in part by the Graduate School Research Fund of the University of Washington, and in part by National Science Foundation grant GP-28881. The work done at Princeton was supported by National Aeronautics and Space Administration contract NAS5-1810.
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University of WashingtonUNSPECIFIED
Subject Keywords:interstellar extinction — interstellar matter
Record Number:CaltechAUTHORS:20190529-161902094
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:95899
Deposited By: George Porter
Deposited On:31 May 2019 15:16
Last Modified:16 Nov 2021 17:16

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