40-350 Micron emission from dust in NGC2023
A source of far infrared radiation associated with the reflection nebula and molecular cloud NGC2023 has been detected. Combination of this observation with satellite ultraviolet observations of the exciting star (HD37903, B1. 5V) indicates that the energy radiated by dust in the far infrared is balanced by the ultraviolet stellar energy absorbed by the dust.
Comparison of this source with OMC2 and the Kleinmann-Low nebula suggests that the dust temperature is roughly proportional to the gas temperature (which is given by the CO excitation temperature) for ice, silicate or graphite grains. If the dust and gas temperatures are equal and the grains are made of ice the gas to dust ratios in all three objects are close to the value in the interstellar medium.