Science:
Planetary systems are born around young stars and grow from
vast clouds of dust and gas called protoplanetary disks. Models
predict that as our own solar system's protoplanetary disk
evolved, the dust and gas pushed each other around while
constantly being stirred and jolted by magnetic fields and
gravitational torques. The resulting mixing and motion set the
chemical compositions of the planetesimals that formed and from
which planets eventually grew. Although evidence for mixing is
found in objects in our solar system, such as primitive
meteorites, questions remain about the details of the processes
responsible and whether this mixing was common in other
protoplanetary disks. A
new
paper in Science on observations of the disk around the
star AA Tau that suggest that we will soon be able to address
these questions.
