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EMBARGOED UNTIL 11:30 A.M. PACIFIC TIME JUNE 8, 1993
NASA astronomers investigating how stars are born have used a new approach to observe the motion of multiple clumps of interstellar gas that are on the verge of becoming new stars and planetary systems.
This experiment was performed with the new instruments developed for NASA's High Resolution Microwave Survey (HRMS), which is searching for radio signals that may be coming from technological civilizations on planets orbiting distant stars.
HRMS is part of NASA's Toward Other Planetary Systems (TOPS) program, which is designed to find and study planets forming around other stars.
Our Milky Way galaxy contains large, massive interstellar clouds of gas which are the nurseries for newborn stars. Astronomers believe gravity causes these clouds to collapse and fragment and produce smaller, dense clumps of gas. In time these clumps collapse to form protostars, and ultimately stars and planetary systems.
"We hope that by finding and characterizing these small, dense clumps of gas we can understand the star formation process and why different types of stars evolve," said Dr. Thangasamy "Velu" Velusamy, a member of the research team at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
One way to study interstellar clouds is to detect the radio emissions that are produced by a variety of molecules that are found in the gas clouds.
The JPL scientists observed that radio emissions from a carbon-sulfur chain molecule called CCS, stand out much more clearly in some of these gas clumps.
"We found that these parcels of gas have very little or no internal motion, other than random motions of individual molecules at very low temperatures (20 K). For this reason we believe that we are seeing the basic cloud fragments from which stars may form," said Dr. William Langer, leader of JPL's Radio Astronomy Group.
To detect the radio waves in the star-forming clouds, scientists used the large 70-meter (230-foot) radio telescope at NASA's Deep Space Network in Goldstone, Calif. in conjunction with the 2 million channel wide-band spectrum analyzer that is the heart of the HRMS sky survey system.
"What made our observations unique was that we were able to take advantage of the HRMS spectrum analyzer to separate out the motions of individual clumps of gas, which gave us unprecedented velocity resolution," said Langer.
"Using this instrument with the large radio telescope allows us to detect small scale structure in a star-forming region and study their motions with respect to one another. This is especially important to resolve the questions of how stars form and why some stars form alone, while others form companion systems orbiting one another," Langer continued.
In collaboration with Langer and Velusamy, Drs. Thomas Kuiper, Steven Levin and Edward Olsen presented their findings before the 182nd national meeting of the American Astronomical Society at the University of California at Berkeley.
Velusamy, director of the Ooty Radio Observatory in India, is on sabbatical leave as a U.S. National Research Council senior resident research associate at JPL.
The research performed by JPL's Radio Astronomy Group was conducted under contract with NASA. HRMS is sponsored by the Solar System Exploration Division of NASA's Office of Space Science, NASA Headquarters, Washington, DC.