Properties of dust in the Orion nebula.

Abstract

New observations of the Orion nebula very close to the Trapezium stars have been taken with the IUE satellite in order to improve knowledge of the dust properties in the nebula. The new data have been interpreted together with previous observations using multiscattering models with various distributions of the dust-to-gas ratio. The main result is that a single kind of dust cannot explain the radial behavior of the scattered light. A possibility is that of a relatively large dust 'cavity', such that the grains closer to the illuminating stars scatter in the UV more forward than the more distant ones. The albedo remains the same for all the grains, and moreover approximately constant with the wavelength, from the visual to the UV (mean omega value of about 0.45).