ALMA reveals a magnetically-regulated scenario for protostellar collapse: B335 & future perspectives.

Understanding the first steps in the formation of stars and protoplanetary disks is a great unsolved problem of modern astrophysics. Observationally, the key to constraining theoretical models lies in high-resolution studies of the youngest protostars. I will show our SMA and ALMA observations of the magnetic field topology in a sample of young protostars, and especially in the nearby B335 protostar where our ALMA observations have allowed to identify for the first time a scenario of magnetically-regulated collapse (Maury+ 2018). I will show how ALMA observations of the youngest, Class 0, disks confirm our early results (Maury+ 2019) that most young protostellar disks (>75%) are only found at very small radii