The amount of gas that is converted into stars by the star formation process is described by the star formation rate. For instance, in the Milky Way today between 0.7 and 1.5 solar masses of gas are converted into stars each year. However, this a mean value across our Galaxy, since locally clouds can start forming stars at higher rates
Some main sequence stars shows an excess of emission in far infrared with respect to photospheric values. This emission is thought to be thermal emission of dust grains and solid bodies associated with a debris disk orbiting around stars. This hypothesis has been confirmed when some of these disks, such as the one orbiting the star Fomalhaut, have been directly
