Radiation from a baby star

X-ray telescopes have captured the earliest and clearest view of the core of a gas cloud about to transform into a star. Most intriguing to astronomers is evidence suggesting that some force other than gravity is hastening the transition.

BABY BLAST. X rays (arrow) detected from an embryonic star. Hamaguchi, et al., NASA, ESA

The X rays from the cloud, known as a class 0 protostar, mark the first clear detection of high-energy radiation from such an early stellar precursor. To produce the X rays, the infalling gas within the protostar must be fast moving and extremely hot.

“This is no gentle freefall of gas,” notes Michael Corcoran of NASA’s Goddard Space Flight Center in Greenbelt, Md.

He and his colleague suggest that the sudden release of energy stored in tangled magnetic fields within the spinning protostar accelerated the gas. A similar process gives rise to flares spewed by the sun.

The team relied on data from several telescopes. The European Space Agency’s XMM-Newton, with its superior capacity to record faint X-ray sources, made the initial detection. NASA’s Chandra X-ray Observatory then pinpointed the location of the source, which lies in the stellar nursery R Coronae Australis. The infrared Subaru telescope measured the protostar’s distance to Earth, about 500 light-years.

Corcoran, Kenji Hamaguchi of Goddard, and their colleagues describe their findings in an upcoming Astrophysical Journal.

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