High Resolution Mapping of the Orion Nebula Region at 30, 50 and 100 Microns

Abstract

The central ~4’ x 4’ region of the Orion Nebula-OMC1 complex has been mapped with 20” resolution in well-defined bands at 30, 50, and 100 µ from the NASA C-141 infrared observatory. These data provide detailed information about the distribution of matter, luminosity, and temperature in this region. The principal results are the following: A) At all three wavelengths, the surface brightness peaks sharply at the position of the infrared cluster, which includes the Becklin-Neugebauer and Kleinmann-Low objects, to the northwest of the Trapezium. The total 25 to 130 µ luminosity from a 30” region centered on this peak is 4 x 10⁴ L_O. B) This emission peak is resolved spatially at all three wavelengths, with a characteristic half-width of 35”. C) The color temperature of the emission at the peak is ~120 K. The temperature decreases uniformly away from this peak as expected for a dust cloud heated by a central luminosity source. D) At all three wavelengths, the surface brightness of the emission in the direction of the H II region is measured to be less than 10% of the peak surface brightness. The color temperature of this emission is ≤ 200 K. E) At 50 µ and 100 µ, there is a strong suggestion of a ring of emission surrounding the H II region, which is well-correlated with the position of optically visible ionization fronts. F) The previously identified bar of emission associated with the ionization front near θ²A Orionis is not resolved at any wavelength and is smaller than 30’ in NW-SE extent. G) The total 25–130 µ emission from the region mapped is ~ 2 x 10 L_O, The infrared cluster and the Trapezium cluster appear to make roughly equal contribution to this luminosity.