Multiple scattering in reflection nebulae. II. Uniform plane-parallel nebulae with foreground stars

Journal Article · Thu Sep 01 04:00:00 EDT 1977 · Astrophys. J., Suppl. Ser.; (United States)

DOI:https://doi.org/10.1086/190464· OSTI ID:7290815

Witt, A N

Parametrized Monte Carlo model calculations are presented for the surface brightness of a plane-parallel, uniformly dense nebula which is illuminated by a foreground star. The effects of relevant parameter changes are examined graphically after representing the computed surface brightness distribution by a power law. Despite substantial multiple scattering, the shape of the phase function remains dominant in affecting the predicted surface brightness distributions. In optically thick nebulae the brightness is essentially determined by the density of the nebula near the front surface rather than the total optical depth. Multiple scattering effects strongly increase in importance with increasing angular distance from the star, significantly lessening the steepness of the surface brightness distribution compared to single-scattering models. The observational approach of deriving relative radar cross sections by the extrapolation of observed color differences to 0/sup 0/ offset has been tested with the present models, and we find that despite multiple scattering, such an approach will produce reasonably accurate results.

• Research Organization: Ritter Astrophysical Research Center, The University of Toledo
• OSTI ID: 7290815
• Journal Information: Astrophys. J., Suppl. Ser.; (United States), Journal Name: Astrophys. J., Suppl. Ser.; (United States) Vol. 35:1; ISSN APJSA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALBEDO
BRIGHTNESS
ELEMENTARY PARTICLES
INTERSTELLAR GRAINS
MASSLESS PARTICLES
NEBULAE
OPACITY
OPTICAL PROPERTIES
PARTICLES
PHASE SHIFT
PHOTONS
PHYSICAL PROPERTIES
RADIATION TRANSPORT