Using far-infrared limb brightening to probe isolated dark globules

Journal Article · Wed Feb 01 04:00:00 EST 1989 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/167103· OSTI ID:6141885

Leung, C M; O'brien, E V; Dubisch, R

The problem of radiation transport in dark globules with or without internal heat source, immersed in an isotropic incident interstellar radiation field, is solved. The phenomenon of infrared limb brightening, its dependence on cloud properties, and its observational implications are addressed. Numerical results regarding the dependence of limb brightening on total cloud opacity, luminosity of internal heat source, grain type, dust density distribution, and wavelength of emitted radiation are discussed. Observational implications concerning the use of limb brightening to place an upper limit on the luminosity of an embedded protostar and to determine the grain emissivity law in the far-infrared are examined. For sufficiently large optical depth, the limb-brightening ratio (LBR) is found to be related to the optical depth by a power-law relation in the 140-300 micron wavelength range, where thermal emission from grains peaks. By observing the LBR in this range, this power-law relationship can be exploited to determine the emissivity law of the dust grain in the far-infrared. Both the LBR and the longest wavelength for which limb brightening still occurs are related linearly to the luminosity of the central source. 37 references.

• Research Organization: Rensselaer Polytechnic Inst., Troy, NY (USA); Rensselaer Polytechnic Institute, Troy, NY (USA); Siena College, Loudonville, NY (USA)
• OSTI ID: 6141885
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 337; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC DUST
DENSITY
DUSTS
ELECTROMAGNETIC RADIATION
FAR INFRARED RADIATION
INFRARED RADIATION
INFRARED SPECTRA
INTERSTELLAR GRAINS
INTERSTELLAR SPACE
LIMITING VALUES
LUMINOSITY
NEBULAE
OPACITY
OPTICAL PROPERTIES
PARTICLES
PHYSICAL PROPERTIES
PROTOSTARS
RADIATION TRANSPORT
RADIATIONS
SPACE
SPECTRA