Scientists have presented new study that is supporting one of the theories about the formation of binary-stars.
The Astrophysical Journal
Binary star is a pair of stars that revolve around their common center of mass under mutual gravitational attraction. Nearly half of all Sun-like stars comprise double or multiple-star systems but the mechanism behind the formation of such systems was not clear.
“The only way to resolve the debate is to observe very young stellar systems and catch them in the act of formation,” said John Tobin, of the National Radio Astronomy Observatory (NRAO). “That’s what we’ve done with the stars we observed, and we got valuable new clues from them,” he added.
Their new clues support the idea that double-star systems form when a disk of gas and dust whirling around one young star fragments, forming another new star in orbit with the first. Young stars that still are gathering matter from their surroundings form such disks, along with jet-like outflows rapidly propelling material in narrow beams perpendicular to the disk.
Astronomers found two companions in the plane of the disks of gas-enshrouded young stars located about 1,000 light-years away from Earth.
“This fits the theoretical model of companions forming from fragmentation in the disk,” Tobin explained. “This configuration would not be required by alternative explanations.”
This discovery supports the disk-fragmentation idea.
“Our new findings, combined with the earlier data, make disk fragmentation the strongest explanation for how close multiple star systems are formed,” said Leslie Looney of NRAO and the University of Illinois.
“The increased sensitivity of the (Very Large Array) VLA, produced by a decade-long upgrade project completed in 2012, made the new discovery possible,” Claire Chandler of NRAO said.
New studies give strong boost to binary-star formation theory – EurekAlert (http://goo.gl/o1zBHy)
John J. Tobin et al. (2013). VLA and CARMA Observations of Protostars in the Cepheus Clouds: Sub-arcsecond Proto-binaries Formed via Disk Fragmentation The Astrophysical Journal DOI: 10.1088/0004-637X/779/2/93