National Radio Astronomy Observatory | ALMA | 2016 Feb 12
Using ALMA, astronomers have taken a new, detailed look at the very early stages of planet formation around a binary star. Embedded in the outer reaches of a double star's protoplanetary disk, the researchers discovered a striking crescent-shape region of dust that is conspicuously devoid of gas. This result, presented at the AAAS meeting in Washington, D.C., provides fresh insights into the planet-forming potential of a binary system.Artist impression of the HD 142527 binary star system based on data from the
Atacama Large Millimeter/submillimeter Array (ALMA). The rendition shows a
distinctive arc of dust (red) embedded in the protoplanetary disk. The red arc
is free of gas, suggesting the carbon monoxide has "frozen out," forming a
layer of frost on the dust grains in that region. Astronomers speculate this
frost provides a boost to planet formation. The two dots in the center
represent the two stars in the system. Credit: B. Saxton (NRAO/AUI/NSF)
Astronomers struggle to understand how planets form in binary star systems. Early models suggested that the gravitational tug-of-war between two stellar bodies would send young planets into eccentric orbits, possibly ejecting them completely from their home system or sending them crashing into their stars. Observational evidence, however, reveals that planets do indeed form and maintain surprisingly stable orbits around double stars.
To better understand how such systems form and evolve, astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) took a new, detailed look at the planet-forming disk around HD 142527, a binary star about 450 light-years from Earth in a cluster of young stars known as the Scorpius-Centaurus Association.
The HD 142527 system includes a main star a little more than twice the mass of our Sun and a smaller companion star only about a third the mass of our Sun. They are separated by approximately one billion miles: a little more than the distance from the Sun to Saturn. Previous ALMA studies of this system revealed surprising details about the structure of the system's inner and outer disks. ...