Thursday 18 February at 2:30pm

Michiel Hogerheijde - UC Berkeley

"The molecular environment of low-mass protostars"

ABSTRACT: "Stars form when condensations in dense molecular clouds collapse under their own gravity. Understanding the relative influence of the cloud's weak magnetic field, its rotation, and the bipolar wind from the young star on the formation process, requires detailed observations of the structure of the collapsing envelopes around embedded protostars. I will present results of a recent study of low-mass, embedded young stellar objects, using dust-continuum and molecular-line data obtained at (sub) millimeter wavelengths with single-dish (JCMT, CSO) and aperture-synthesis (OVRO) techniques. These observations reveal the presence of circumstellar disks, the density structure in the collapsing envelopes, and the impact of the outflows on the envelopes on scales down to 700 AU. Two-dimensional Monte-Carlo simulations of the molecular excitation and radiative transfer allow realistic comparison with theoretical models of collapsing clouds and bipolar outflows."