Monte Carlo simulation of temperature fluctuations in interstellar iron grains

The Monte Carlo technique is used to simulate the temperature fluctuations in interstellar iron grains exposed to a particular radiation field. It is found that iron grains attain time-averaged temperatures almost an order of magnitude greater than dielectrics and that their temperatures may fluctuate by as much as 100 K. The effect that this will have on the catalytic formation of molecular hydrogen is examined. It is also found that small metallic grains are unlikely candidates for explaining the extended red emission observed in many reflection nebulae.