How does material move through an accretion disk to the young star at its center? Surprising detections from a fortuitously angled disk have now provided new insights.
When stars are born from the collapse of a dense molecular cloud, they spend their early stages surrounded by circumstellar disks: disks of gas and dust that we understand to be accreting onto the young stars at their centers.
Herschel infrared view of the Taurus Molecular Cloud complex, the home of GV Tau. [ESA/Herschel/NASA/JPL-Caltech; acknowledgement: R. Hurt (JPL-Caltech)]How do we know that the disk matter is flowing onto the stars? Evidence for accretion comes from the high-energy light emitted when inflowing material strikes the surface of young stars, producing accretion shocks. But, though these observations provide evidence that accretion is occurring, they don’t tell us much about the mechanisms that drive these flows within the disk.
For material to move inwards within a disk, it must first lose angular momentum — but where does that momentum go? What processes remove or redistribute it? In a new study led by Joan Najita (NSF’s NOIRLab), a team of scientists presents high-resolution observations of an unusual disk — one that happens to be angled ...