However, its distribution is traced by other molecules which have a rich spectrum of radio-frequency line emission. Many species have been detected in the ISM, ranging from carbon monoxide to water to formaldehyde to alcohol. Think of the difference between looking at a clear blue sky and a cloudy one. Interplanetary dust also reddens starlight, and causes it to become polarized. The energy it radiates is provided by a continued slow shrinkage, converting gravitational energy into heat to replace the energy which the protostar is radiating away.
More massive stars go through each stage far more rapidly than less massive ones.
Copyright 1999 by James N. Douglas. All rights reserved.