ANGULAR MOMENTUM EVOLUTION OF YOUNG LOW-MASS STARS AND BROWN DWARFS: OBSERVATIONS AND THEORY

J. Bouvier (IPAG Grenoble, France),
S. Matt (CEA Saclay, France),
S. Mohanty (Imperial College London, United Kingdom),
A. Scholz (Dublin Institute for Advance Studies, Ireland),
K. Stassun (Vanderbilt University, United States),
C. Zanni (Osservatorio Astronomico di Torino, Italy)

Spectacular progress has been made, both on the observational and theoretical sides, on the issue of the angular momentum evolution of young stellar objects since PPV. On the observational side, thousands of new rotational periods have been derived for stars over the entire mass range from solar-type stars down to brown dwarfs at nearly all stages of evolution between birth and maturity. The picture we have of the rotational evolution of low- mass and very low-mass stars and brown dwarfs has never been as well documented as of today. On the theoretical side, recent years have seen a renaissance in numerical simulations of magnetized winds that are the prime agent of angular momentum loss, new attempts have been made to understand how young stars exchange angular momentum with their disks via magnetic interactions, and new insights have been gained on the way angular momentum is transported in stellar interiors. Our chapter will review the latest developments which shed new light on the processes governing the angular momentum evolution of young stars and brown dwarfs, and also provide important context for other PPVI chapters by exploring possible connections between the rotational history of stars and the formation, migration and evolution of planetary systems (star-disk interaction, inner disk warps and cavities, planet engulfment, irradiation of young planets, etc.). We aim at providing the most complete review of both the emerging concepts and the latest observational results regarding the angular momentum evolution of young low-mass stars and brown dwarfs.

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