Atomic gas Molecular clouds Atomic and molecular gas in the galaxy M33 (Engargiola et al. 2003)

M51 in CO emission (left) and optical (right) (Koda et al., 2009)

Pipe Nebula (Lombardi, Alves, & Lada 2006) -- extinction Pipe Nebula (Lombardi, Alves, & Lada 2006) -- optical

The Perseus molecular cloud in 13CO J=2-1, integrated over velocity (Sun et al. 2006)

Infrared image of the W5 region from Spitzer

The core B68 in a wide variety of tracers.

Evolutionary tracks in the HR diagram for stars from 0. 6 - 6 M Evolutionary tracks in the HR diagram for stars from 0.6 - 6 M. Only lower mass stars have a Hayashi track.