By Daniel Stolte, University Communications June 10, 2010
For the first time, astronomers have observed solar systems in the making in great detail.
A team led by University of Arizona astronomer
Joshua Eisner has observed in unprecedented detail the processes giving rise to stars and planets in nascent solar systems.
By coupling both Keck telescopes on Mauna Kea in Hawaii with a specifically engineered instrument named ASTRA (ASTrometric and phase-Referenced Astronomy), Eisner and his colleagues were able to peer deeply into protoplanetary disks – swirling clouds of gas and dust that feed the growing star in its center and eventually coalesce into planets and asteroids to form a solar system.
The big challenge facing Eisner’s team lies in obtaining the extremely fine resolution necessary to observe the processes that happen at the boundary between the star and its surrounding disk – 500 light years from Earth. It’s like standing on a rooftop in Tucson trying to observe an ant nibbling on a grain of rice in New York’s Central Park.
“The angular resolution you can achieve with the Hubble Space Telescope is about 100 times too coarse to be able to see what is going on just outside of a nascent star not much bigger than our sun,” said Eisner, an assistant professor at UA’s Steward Observatory. In other words, even a protoplanetary disk close enough to be considered in the neighborhood of our solar system would appear as a featureless blob.
Combining the light from the two Keck telescopes provides an angular resolution finer than Hubble’s. Eisner and his team used a technique called spectro-astrometry to boost resolution even more. By measuring the light emanating from the protoplanetary disks at different wavelengths with both Keck telescope mirrors and manipulating it further with ASTRA, the researchers achieved the resolution needed to observe processes in the centers of the nascent solar systems.