Infrared Energy Distributions and the Nature of Young Stellar Objects

Abstract

The formation and early evolution of stars in our galaxy occurs in dense regions of molecular clouds, where newly formed stars are physically associated with varying amounts of gas and dust that alter their observed appearance. Indeed, the actual star formation process and the youngest stellar objects themselves are rendered completely invisible by the obscuration of opaque circumstellar dust. As a consequence, a significant fraction of the luminous energy of a young stellar object is radiated in the infrared portion of the electromagnetic spectrum. Infrared observations therefore offer a powerful tool for studying the earliest phases of stellar evolution and perhaps even star formation itself. Recent studies of the infrared energy distributions of young objects have resulted in a new and clearer understanding of the processes involved in the formation and early evolution of low mass stars. In this paper some of the more interesting results of these investigations are reviewed.