Emission from dust in visual reflection nebulae at infrared and submillimeter wavelengths

Journal Article · Mon Apr 01 00:00:00 EST 1991 · Astrophysical Journal; (United States)

DOI:https://doi.org/10.1086/169882· OSTI ID:5666620

Casey, S C ^[1]

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1. NASA, Goddard Space Flight Center, Greenbelt, MD (USA) Yerkes Observatory, Williams Bay, WI (USA)

Far-IR and submillimeter images of five bright visual reflection nebulae, IC 446, NGC2247, NGC 2245, NGC 7023, and CED 201 are presented and used with composite IR spectra to derive parameters such as the fraction of nebulae emission attributed to molecule-sized grains, the range of nebulae grain albedos, gas densities, and gas cloud geometries. The results show that 30-45 percent of the nebulae emission lies at wavelengths of less than 30 microns. The variation in IR luminosity may be related to variations in nebulae gas density and less than optimal gas cloud geometries rather than to anomalous grain albedos. Relative extinction efficincies of roughly 1000-5000 are inferred for stellar photospheres with effective wavelengths of roughly 0.25-0.5 micron. The resultant mass-extinction coefficient is roughly 10-50 sq cm/g. 79 refs.

• OSTI ID: 5666620
• Journal Information: Astrophysical Journal; (United States), Vol. 371; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
NEBULAE
EMISSION SPECTRA
COSMIC DUST
COSMIC GASES
FAR INFRARED RADIATION
IMAGES
INFRARED SPECTRA
INTERSTELLAR GRAINS
LUMINOSITY
STELLAR ATMOSPHERES
VARIATIONS
ATMOSPHERES
DUSTS
ELECTROMAGNETIC RADIATION
FLUIDS
GASES
INFRARED RADIATION
OPTICAL PROPERTIES
PARTICLES
PHYSICAL PROPERTIES
RADIATIONS
SPECTRA
640105* - Astrophysics & Cosmology- Galaxies