The rotation of a star and the revolutions of its planets are not necessarily aligned. This
article reviews the measurement techniques, key findings, and theoretical interpretations …

Context. In the past few years, there has been a rise in the detection of streamers,
asymmetric flows of material directed toward the protostellar disk with material from outside …

Context. Transition disks are protoplanetary disks with dust-depleted cavities, possibly
indicating substantial clearing of their dust content by a massive companion. For several …

While dust disks around optically visible, Class II protostars are found to be vertically thin,
when and how dust settles to the midplane are unclear. As part of the Atacama Large …

The demographic of circumstellar disks, the birthplaces of planets, is diverse and rich in
disks featuring rings, gaps, spirals, filaments, and arcs. Many studies revealing these disk …

Context. While it is generally assumed that Class II sources evolve largely in isolation from
their environment, many still lie close to molecular clouds and may continue to interact with …

MHD models and the observation of accretion streamers confirmed that protostars can
undergo late accretion events after the initial collapse phase. To provide better constraints …

The concentric gaps and rings commonly observed in protoplanetary disks in millimeter
continuum emission have lent the impression that planet formation generally proceeds …

Context. The infall of gas from outside natal cores has proven to feed protostars after the
main accretion phase (Class 0). This changes our view of star formation to a picture that …

Close encounters between young stellar objects in star-forming clusters are expected to
markedly perturb circumstellar disks. Such events are witnessed in numerical simulations of …