March 2, 2011
Disks around young distant stars likely forming into planets
A University of Washington astronomer is part of an international team that for the first time has captured detailed images of planet-forming disks around two young stars more than 400 light years from Earth.
The team of more than 100 scientists from 25 institutions, including John Wisniewski, a UW postdoctoral researcher in astronomy, produced images that show how planets might have formed from the disks of material around the stars.
The team studied a star called LkCa15, about 450 light years from Earth, and one called AB Aur, about 470 light years away (a light year, the distance light travels in a year, is about 6 trillion miles).
The collaboration said the image of AB Aur shows fine disk structures comparable to what might be found near Neptune in our solar system. Irregularities that include the presence of tilted double rings and a void of empty space between the rings indicate at least one giant, Jupiter-like planet is affecting the disk.
The image of LkCa15 shows a central gap in the disk of material around the star, and the scientists say the lack of material near the central star implies that a giant planet is gathering in material from the disk that the star hasnt consumed already.
Wisniewski said the images provide evidence for planet formation on the scale of our solar system. He added that the project could eventually aid in understanding how Earthlike habitable zones develop. He and the other scientists are analyzing later images of LkCa 15 in polarized light to learn more about the nature of the apparent gap in its disk.
The images were captured using the Japanese Subaru telescope at the summit of Mauna Kea on the island of Hawaii. The findings from the Strategic Explorations of Exoplanets and Disks with Subaru collaboration are published in Astrophysical Journal Letters.