The birth of two stars like our sun -- emerging from wombs of interstellar dust and gas--is being witnessed for the first time by astronomers using a new satellite-based infrared telescope.
The two "protostars," as young as 100,000 to 1 million years old, were discovered in data taken during the first two weeks of operation of the Infrared Astronomical Satellite. The data were taken in February, but are only now completing computer analysis.
The new stars were found in the center of two dark dust clouds, one near the constellation Taurus and the other near the constellation Epidaurus. The dust clouds are called Barnard 5 and Lynds 1642.
Although coalescing stars hundreds to thousands of times brighter than the sun have been spotted, the sightings announced last week by the Jet Propulsion Laboratory in California and NASA are the first ones of the birth of stars as small as the sun.
The two stars, along with hundreds and perhaps thousands of others which now can be seen with the sensitive satellite instrument at various stages of the stars' birth, may answer a number of fundamental questions about star formation, said Charles Beichman, an astrophysicist senior scientist at JPL.
Stars are created as clouds of dust and gas condense into clumps of matter, and begin attracting more and more matter by gravity. But scientists do not know how much material is needed in a cloud to start the process.
It is also believed that it may require some triggering physical conditions or event, such as the explosion of a nearby star, to begin the formation of clumps of matter that finally grow, become greatly compressed and heat up to the point that they begin thermonuclear chain reactions that make stars shine.
Scientists working with the infrared satellite hope to find hundreds more of the young, dim stars that cannot be easily seen from Earth. Thus, by catching stars at various stage of birth, they hope to be able to answer a few fundamental questions about the birth of stars as it is now going on in our galaxy.
The IRA satellite is operated jointly by the United States, the United Kingdom and the Netherlands. It began sending back data Jan. 31 and will continue its survey until next January.