Star Caught in Act of Birth
By Denise Chow
SPACE.com Staff Writer
posted: 21 June 2010
01:05 pm ET
The youngest unborn star currently known – an object so early in its formation that it isn't fully developed into a true star – has been caught on camera in a new study.
Astronomers glimpsed the future star using the Submillimeter Array in Hawaii and the infrared Spitzer Space Telescope. The object, which is estimated to be only a few thousand years old, has just begun pulling matter in from a surrounding envelope of gas and dust.
"It's very difficult to detect objects in this phase of star formation, because they are very short-lived and they emit very little light," said lead author Xuepeng Chen, a postdoctoral associate at Yale University, in a statement. [Photos: The infrared universe.]
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www.AlignGI.comThe team of astronomers was able to detect the faint light emitted by the dust surrounding the object. In the images, however, the object is difficult to see because that light is not emitted in infrared wavelengths, a press representative from Yale University told SPACE.com.
The object, known as L1448-IRS2E, is located in the Perseus star-forming region, which is approximately 800 light-years away, within our own Milky Way galaxy. Early calculations estimate that the object is approximately a few thousand years old, the Yale spokesperson said.
The study's authors include astronomers from Yale, the Harvard Smithsonian Center for Astrophysics, and the Max Planck Institute for Astronomy in Germany. The study was published in the June 1 issue of the Astrophysical Journal.
Stars form from large, dense regions of gas and dust called molecular clouds, which exist throughout the galaxy.
The researchers suspect that L1448-IRS2E is in between the pre-stellar phase - when a particularly dense region of a molecular cloud first begins to clump together - and the protostar phase, when gravity has pulled enough material together to form a dense, hot core out of the surrounding envelope.
Typically, most protostars are between one to 10 times as luminous as our sun, and their large, dust envelopes glow at infrared wavelengths. But, since L1448-IRS2E is less than one-tenth as luminous as the sun, the astronomers believe that the object is simply too dim to be considered a true protostar.
They have, however, discovered that the object is ejecting streams of high-velocity gas from its center, which confirms that some sort of preliminary mass has already formed, and the object has developed beyond the pre-stellar phase.
This ejection of material is seen in protostars as a result of the magnetic field surrounding the newly-forming star. But, this outflow has not been observed at such an early stage until now.
The researchers are hoping to use the new Herschel space telescope, which launched in May 2009, to look for more of these objects that are caught between the earliest stages of star formation. This will allow astronomers to better understand how stars grow and evolve
"Stars are defined by their mass, but we still don't know at what stage of the formation process a star acquires most of its mass," said Hector Arce, one of the authors of the study and an assistant professor of astronomy at Yale University. "This is one of the big questions driving our work."
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