circumstellar disks tagged posts

Combined ALMA and VLA image of L1448 IRS3B system. Credit: Bill Saxton, ALMA (ESO/NAOJ/NRAO), NRAO/AUI/NSF

For the first time, astronomers have seen a dusty disk of material around a young star fragmenting into a multiple-star system. Scientists had suspected such a process, caused by gravitational instability, was at work, but new observations with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA) revealed the process in action.

“This new work directly supports the conclusion that there are two mechanisms that produce multiple star systems – fragmentation of circumstellar disks, such as we see here, and fragmentation of the larger cloud of gas and dust from which young stars are formed,” said John Tobin, of the University of Oklahoma and...

Planetary disk around the star known as TW Hydrae. Credit: S. Andrews (Harvard-Smithsonian CfA); B. Saxton (NRAO/AUI/NSF); ALMA (ESO/NAOJ/NRAO)

The dusty disk surrounding star TW Hydrae exhibits circular features that may signal the formation of protoplanets. An astrophysicist argues, however, that the innermost actually points to the impending dispersal of the disk. When the maps appeared at the end of March, experts were electrified. The images revealed an orange-red disk pitted with circular gaps: a detailed portrait of a protoplanetary disk, made up of gas and dust grains, associated with a young star – the kind of structure out of which planets could be expected to form...

A computer model reproduces the two-spiral-arm structure; the “x” is the location of a putative planet. The planet, which cannot be seen directly, probably excites the two spiral arms. Credit: NASA, ESA, ESO, M. Benisty et al. (University of Grenoble), R. Dong (Lawrence Berkeley National Laboratory), and Z. Zhu (Princeton University)

This idea not only opens the door to a new method of planet detection, but also could offer a look into the early formative years of planet birth. Though astronomers have cataloged thousands of planets orbiting other stars, the earliest stages of planet formation are elusive because nascent planets are born and embedded inside vast, pancake-shaped disks of dust and gas encircling newborn stars, known as circumstellar disks.

The conclusion that planets may betr...