Six teams of scientists have been selected to participate in
the first new mission of NASA’s Origins Program, a project which will seek to answer the questions: Where did we come from? Are we alone?
Researchers will make their observations with the new Space Infrared Telescope Facility (SIRTF), now set for launch in July 2002. The teams will study the formation of galaxies, stars and planet-forming dust disks with the space-based telescope.
The teams were chosen from 28 proposals submitted by astronomers worldwide. They make up the SIRTF Legacy Science Program, which will involve American-led teams of scientists from around the world. The six projects comprise more than 3,000 hours of observations, or about half of SIRTF’s first year of operation.
* Galaxy Birth and Evolution This project will probe the farthest reaches of the universe to image the most distant objects that can be seen by SIRTF and to help answer questions about the birth and evolution of galaxies to a distance of 12 billion light-years. The project will photograph  0.08 square degrees, or about 1/500,000th of the entire sky. This area is equivalent to the size of an American quarter held at a distance of about four feet (1.2 meters). Led by Dr. Mark Dickinson of the Space Telescope Science Institute in Baltimore, MD, this project uses 647 hours of observing time.
* Black Holes and Galaxies. A companion survey will use both SIRTF infrared cameras to cover an area of the sky equivalent to about 500 full Moons, or 100 square degrees of sky. Images produced will help astronomers study the evolution of dusty galaxies up to 10 billion light-years from Earth. The survey will determine whether black holes are the primary energy source in bright distant galaxies, or whether massive bursts of star formation can provide the necessary light. Led by Dr. Carol Lonsdale of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, CA, This project uses 851 hours of SIRTF observing time.
* Unveiling Hidden Stars. This investigation will study 75 nearby galaxies, conducting comprehensive imaging to pierce the dust that hides star formation. This research will yield new insights into the physical processes connecting star formation to the interstellar medium of dust and gas that permeates galaxies. Led by Dr. Robert Kennicutt of the University of Arizona in Tucson, the project uses 512 hours of
SIRTF time.
* Inside the Milky Way. This large-area survey of the inner portion of our Milky Way galaxy will produce an invaluable database for the larger astronomical community. Because the central regions of our galaxy are heavily obscured by dust, they remain hidden from optical telescopes. By using SIRTF’s shorter-wavelength infrared camera, this study will lift the opaque, dusty veil to uncover newly formed stars. Observations will yield information about the large-scale structure of the inner Milky Way and uncover details of the star formation process by observing heavily obscured clusters of newborn stars. Led by Dr. Ed Churchwell of the University of Wisconsin at Madison, this investigation uses 400 hours of observing time.
* From Gas to Stars
This project will study the process by which stars form out of giant molecular clouds of gas within our galaxy. It will concentrate on observing dense and embedded cores inside molecular clouds located within 100 light-years of Earth. Its goal will be to follow the history of these clumps of dust and gas as they contract due to gravity and evolve into stars. Scientists expect that some of these newborn stars will have dust disks around them that will ultimately form planetary systems, like our solar system. Led by Dr. Neal Evans II of the University of Texas in Austin, this project uses 400 hours and all three SIRTF instruments.
* Planet Formation: When the Dust Settles. A related Legacy Science project will study evolution of planetary systems from a sample of hundreds of stars up to 100 million years old. It will study time scales involved in the planet-building process. While SIRTF lacks the visual acuity to take pictures of planets around nearby stars, it will easily detect and characterize the dusty disks from which planetary bodies form. This project will yield invaluable information that could help astronomers understand the formation of our own solar system. Led by Dr. Michael Meyer of the University of Arizona in Tucson, the study uses 350 hours of observing time.
Detailed observational planning for these projects will be
conducted throughout 2001, and the actual observations will begin a few months after SIRTF is launched.
The SIRTF mission is managed for NASA by the Jet Propulsion Laboratory (JPL) in Pasadena. JPL is a division of the California Institute of Technology. Additional information about SIRTF and the Legacy Science program is available on the Internet at: