Observation of rotation in star forming regions: clouds, cores, disks, and jets

TL;DR

This review summarizes four decades of observational research on rotation in star forming regions, from clouds to jets, highlighting angular momentum transfer processes crucial for star and planet formation.

Contribution

It compiles and analyzes observational data on rotation across all stages of star formation, emphasizing the role of angular momentum loss mechanisms.

Findings

Rotation detected in molecular clouds, cores, disks, and jets.

Angular momentum decreases by 6-7 orders of magnitude during star formation.

ALMA's capabilities offer new insights into rotational processes.

Abstract

Angular momentum plays a crucial role in the formation of stars and planets. It has long been noticed that parcels of gas in molecular clouds need to reduce their specific angular momentum by 6 to 7 orders of magnitude to participate in the building of a typical star like the Sun. Several physical processes on different scales and at different stages of evolution can contribute to this loss of angular momentum. In order to set constraints on these processes and better understand this transfer of angular momentum, a detailed observational census and characterization of rotation at all stages of evolution and over all scales of star forming regions is necessary. This review presents the main results obtained in low-mass star forming regions over the past four decades in this field of research. It addresses the search and characterization of rotation in molecular clouds, prestellar and protostellar cores, circumstellar disks, and jets. Perspectives offered by ALMA are briefly discussed.