Related papers: Formation and Evolution of Disks around Young Stel…
Star formation is thought to be triggered by the gravitational collapse of the dense cores of molecular clouds. Angular momentum conservation during the collapse results in the progressive increase of the centrifugal force, which eventually…
(abridged) The nature of early Class 0/I protostellar discs is not clearly understood. Early protostellar discs are needed to drive molecular outflows and jets observed in star forming regions, but there has been some debate to how they…
The slow rotation of some young stars and the extreme rotation periods of some Ap stars have so far defied explanation. The absence of sufficiently efficient braking mechanisms for newly formed stars points to the star formation process…
Disk formation in magnetized cloud cores is hindered by magnetic braking. Previous work has shown that for realistic levels of core magnetization, the magnetic field suppresses the formation of rotationally supported disks during the…
Dusty primordial disks surrounding young low-mass stars are revealing tracers of stellar and planetary formation. The evolution and lifetime of these disks define the boundary conditions of the mechanisms of planet formation. Stellar…
The role of outflows in the formation of stars and the protostellar disks that generate them is a central question in astrophysics. Outflows are associated with star formation across the entire stellar mass spectrum. In this review, we…
We investigate the evolution of the relative angle between the stellar rotation axis and the circumstellar disc axis of a star that forms in a stellar cluster from the collapse of a turbulent molecular cloud. This is an inherently chaotic…
This article represents a short review of the variability characteristics of young stellar objects. Variability is a key property of young stars. Two major origins may be distinguished: a scaled-up version of the magnetic activity seen on…
I attempt to summarize our knowledge of planet formation in evolving protoplanetary discs. I first review the physics of disc evolution and dispersal. For most of the disc lifetime evolution is driven by accretion and photoevaporation, and…
We present a review of the interplay between the evolution of circumstellar disks and the formation of planets, both from the perspective of theoretical models and dedicated observations. Based on this, we identify and discuss fundamental…
The standard picture for the formation of disk galaxies has come to face a number of problems related to angular momentum. Numerical simulations produce disks that are too small, and analytical models predict too much low angular momentum…
Dusty protoplanetary disks surrounding young low-mass stars are the birthplaces of planets. Studies of the evolutionary timescales of such disks provide important constraints on the timescales of planet formation. Binary companions,…
We review recent progress in high-resolution imaging of scattered light from disks around young stellar objects. Many new disks have been discovered or imaged in scattered light, and improved instrumentation and observing techniques have…
Disks are ubiquitous in stellar astronomy, and play a crucial role in the formation and evolution of stars. In this contribution we present an overview of the most recent results, with emphasis on high spatial and spectral resolution. We…
The magnetic fields associated with young stellar objects are expected to have an hour-glass geometry, i.e., the magnetic field lines are pinched as they thread the equatorial plane surrounding the forming star but merge smoothly onto a…
We review progress in understanding the formation of galactic disks in the standard cosmogonic scenario involving gravitational clustering of baryons and dark matter and dissipative collapse of the baryons. This scenario accounts remarkably…
Most stars form in a cluster environment. These stars are initially surrounded by discs from which potentially planetary systems form. Of all cluster environments starburst clusters are probably the most hostile for planetary systems in our…
This prospective chapter gives our view on the evolution of the study of circumstellar discs within the next 20 years from both observational and theoretical sides. We first present the expected improvements in our knowledge of…
The radial velocities and direct imaging observations of exoplanets have suggested that the frequency of giant planets may decrease for intermediate-mass stars ($2.5-8\,M_\odot$). The key mechanism that could hinder their formation remains…
Stars form from the gravitational collapse of turbulent, magnetized molecular cloud cores. Our non-ideal MHD simulations reveal that the intrinsically anisotropic magnetic resistance to gravity during the core collapse naturally generates…