Two University of ÃÛÌÇÖ±²¥ at Boulder researchers are part of an international team that has discovered enormously powerful stellar flares in the X-ray portion of the light spectrum emanating from infant stars in the throes of birth.
Professor John Bally and Senior Research Associate Bo Reipurth of the astrophysical and planetary sciences department said the x-ray snapshots of the flares were obtained from the constellation Orion with NASA’s orbiting Chandra X-Ray Observatory. The team found that Class-O "protostars" – which are only about 10,000 years old and equivalent in human terms to a one-day-old baby – were emitting flares a million to a billion times as powerful as those that occur on the sun.
The observations were directed by Katsuji Koyama of Kyoto University in Japan. Other team members include KyotoÂ’s Kensuke Imanishi, Penn State UniversityÂ’s Yohko Tsuboi and ÃÛÌÇÖ±²¥Â’s Bally and Reipurth. Both Bally and Reipurth are associated with ÃÛÌÇÖ±²¥-BoulderÂ’s Center for Astrophysics and Space Astronomy.
The announcement was made today at the meeting of the High Energy Astrophysics Division of the American Astronomical Society in Honolulu.
The strong X-ray flares are believed to be generated by an increasing stellar spin of the protostar as gases from dense molecular clouds enveloping the birthing star begin to fall and accrete onto it. The flares also are believed to be caused by the intense convection, or mass movement of fluids, within the forming star -- a process Bally likened to a "boiling pot of water."
The spin and convection appear to create a strong "dynamo" within stars, the physical process that builds and regulates the magnetic field of stars, including our sun.
"This is the first indirect evidence that these Class-O protostars are generating a magnetic field, which is very exciting," said Bally. The constellation Orion is located about 1,400 light-years from Earth.
As the baby stars condense toward the ignition of hydrogen in the objectÂ’s core, the spin and convection become less active. The stars eventually will settle into a quiet phase much like the sun, said Bally.
EarthÂ’s sun was born in a similar molecular cloud core about five billion years ago, a process that also created the rest of the solar system. After a few million years, hydrogen fusion began in the sunÂ’s core, causing it to become a steadier source of energy that eventually allowed for the development of life on Earth.
NASAÂ’s Marshall Space Flight Center in Huntsville, Ala. manages the Chandra program.