Studies of dust grain properties in infrared reflection nebulae

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168298· OSTI ID:6997230

Pendleton, Y J; Tielens, A G.G.M.; Werner, M W ^[1]

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1. NASA, Ames Research Center, Moffett Field, CA (USA)

A model has been developed for reflection nebulae around luminous IR sources embedded in dense dust clouds. The shape of the IR spectrum is shown to be the result of a combination of the scattering properties of the dust, the spectrum of the illuminating source, and foreground extinction, while geometry plays a minor role. Comparison of the model results with IR observations of the reflection nebula surrounding OMC-2/IRS 1 shows that either a grain size distribution like that found in the diffuse ISM, or consisting of larger grains, can explain the observed shape of the spectrum. However, the absolute intensity level of the scattered light, as well as the observed polarization, requires large grains. By adding water-ice mantles to the silicate and graphite cores, the 3.08 micron ice-band feature observed in the spectra of several IR reflection nebulae has been modeled. It is shown that this ice band arises naturally in optically thick reflection nebulae containing ice-coated grains. 40 refs.

• OSTI ID: 6997230
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 349; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BRIGHTNESS
CARBON
CHEMICAL COMPOSITION
COSMIC DUST
COSMIC RAY SOURCES
DUSTS
ELECTROMAGNETIC RADIATION
ELEMENTAL MINERALS
ELEMENTS
ENERGY SYSTEMS
GRAPHITE
ICES
INFRARED RADIATION
INFRARED SPECTRA
INTERSTELLAR GRAINS
INTERSTELLAR SPACE
LIGHT SCATTERING
MATHEMATICAL MODELS
MINERALS
NEBULAE
NONMETALS
OPTICAL PROPERTIES
OXYGEN COMPOUNDS
PARTICLE SIZE
PARTICLES
PHYSICAL PROPERTIES
POLARIZATION
RADIATIONS
SCATTERING
SILICATES
SILICON COMPOUNDS
SIZE
SPACE
SPECTRA