Saturday, March 05, 2005
Wee Star Seen
Scientists from the European Space Agency and NASA observed for the first time a stellar embryo in a collapsing cloud of hydrogen gas. They said that that the images were "analogous to a baby's first ultrasound."
Using the ESA's XMM-Newton X-ray telescope and NASA's Chandra X-ray Observatory, they said that the object, some 500 light years from Earth in the R Corona Australis star-forming region, is a frigid embryonic star, called a Class 0 protostar. Class 0 protostar is just 10 000 to 100 000 years old. The stellar weather inside the cloud is freezing 33 K (-240 C).
But here's the riddle. The team said that the cloud was too cold to produce X-rays and that "matter [was] falling toward the protostar core 10 times faster than expected from gravity alone." According to accepted models, it takes millions years and a lot of hot dense hydrogen gas to fire up a new star and start belching X-rays.
The scientists now believe that the X-ray bursts were caused by magnetic fields, which "in the spinning protostar core accelerate infalling matter to high speeds, producing high temperatures and X-rays in the process. These X- rays can penetrate the dusty region to reveal the core."
Using the ESA's XMM-Newton X-ray telescope and NASA's Chandra X-ray Observatory, they said that the object, some 500 light years from Earth in the R Corona Australis star-forming region, is a frigid embryonic star, called a Class 0 protostar. Class 0 protostar is just 10 000 to 100 000 years old. The stellar weather inside the cloud is freezing 33 K (-240 C).
But here's the riddle. The team said that the cloud was too cold to produce X-rays and that "matter [was] falling toward the protostar core 10 times faster than expected from gravity alone." According to accepted models, it takes millions years and a lot of hot dense hydrogen gas to fire up a new star and start belching X-rays.
The scientists now believe that the X-ray bursts were caused by magnetic fields, which "in the spinning protostar core accelerate infalling matter to high speeds, producing high temperatures and X-rays in the process. These X- rays can penetrate the dusty region to reveal the core."
