Texas astronomer brings infrared space telescope team to UT-Austin

By McDonald Observatory

May 10, 2002

Austin, TX — A team of astronomers led by UT-Austin’s Neal Evans will meet in Austin today and tomorrow to plan their Legacy Science Project with NASA’s next major Earth-orbiting observatory. The Space Infrared Telescope Facility, or SIRTF, is scheduled for launch January 9, 2003. Evans heads one of six Legacy teams selected to complete major survey projects, which will produce data freely available to all astronomers, with SIRTF.

About a dozen astronomers, along with UT-Austin graduate students, will meet to fine-tune their observing plan, develop teams to work on different science aspects of their project, and discuss how to deal with their SIRTF data, Evans said. His collaborators include Paul Harvey of the UT-Austin astronomy department, and astronomers from the Smithsonian Astrophysical Observatory, The California Institute of Technology, NASA’s Jet Propulsion Laboratory, The University of Pennsylvania, The University of Maryland, and The University of Leiden in the Netherlands.

The main idea of the Legacy Project, called ‘From Molecular Cores to Planet-Forming Disks,’ “is to get as complete a sample as possible of things that are forming stars like the Sun,” Evans said. “We’ll be surveying large areas of molecular clouds, to find anything that will form a star or even something smaller,” he said. This range encompasses failed stars (called brown dwarfs) all the way through to young proto-stars that may be surrounded by forming planets.

The team will make 400 hours of observations with SIRTF. Their sample will be about 1,200 light-years deep. A light-year is the distance light travels in one year, about 5,880 billion miles.

“The great strength of SIRTF is sensitivity,” Evans said. “It will be sensitive to wavelengths emitted by dust orbiting newly forming stars at the same distance that Earth orbits the Sun. Right now, there’s nothing tracing that particular range of distances, which is crucial for the formation of planets like Earth. Other techniques probe either hotter or colder dust” Evans said.

Dust at that distance is heated to about 300 Kelvins (degrees above absolute zero). “At that temperature, dust will emit [light] very effectively at 10 microns,” Evans said. “SIRTF is sensitive to light ranging in wavelength from 3.6 microns to 160 microns.”

Neal J. Evans, II is the Edward Randall, Jr. Centennial Professor in Astronomy at the University of Texas at Austin. His project proposal was selected as a SIRTF Legacy Science Project in November 2000.