Highlights - Volume 508-3 (December IV 2009)

In section 1. Letters to the Editor

“Probing the evolution of molecular cloud structure. From quiescence to birth”, by J. Kainulainen, H. Beuther, T. Henning, and R. Plume, A&A 508, p. L35

Some molecular clouds show signs of abundant star formation and others do not. The difference has never been entirely clear, but the letter from Kainulainen et al. highlighted in this issue goes one step towards quantifying this difference. They using the NIR extinction to find a qualitatively different column density distribution in star forming clouds than in clouds with little star formation. While this may be the effect of star formation rather than the cause, it needs further examination.