Joint Astrophysics Colloquium

Joint Astrophysics Seminar

Understanding How Star Formation Proceeds in the Perseus and Ophiuchus Molecular Clouds

Doug Johnstone

HIA-NRC
&
University of Victoria

The nearby Perseus and Ophiuchus molecular clouds are exceptional laboratories for testing the earliest phases of star formation. Careful consideration of the multi-wavelength surveys of these clouds (in particular 2Mass, Spitzer c2d, and COMPLETE) allows us to measure the column density distributions of the bulk cloud, the location and kinematics of the dense stellar-massed cores, and the distribution of the protostars. As such we can now provide strong constraints for theoretical models or simulations wishing to explain the manner in which stars form within a cloud. Highlights of our results are (1) most of the mass of the cloud is at low column density, (2) dense cores form only in high column density regions, (3) the mass distribution of the dense cores is similar to the IMF, (4) dense cores are mostly thermally supported, (5) dense cores contain only a few percent of the cloud mass, (6) the more concentrated cores are most likely to contain embedded protostars, and (7) the dense cores are not randomly located within the the molecular cloud, suggesting possible triggering mechanisms for their creation. In this talk, I will discuss each of these important results and place them in context with theoretical models and simulations of star formation.