Ultrasound for stars’ reveals stellar embryos

A telescope that works like "ultrasound for stars" has found a hatchery filled with massive stellar embryos in a dark cloud of cosmic dust, astronomers reported today.

Looking at the universe by tracking infrared radiation, the Spitzer Space Telescope has found a glowing incubator for developing stars in a bright cloud called the Trifid Nebula.

The embryos are invisible to optical telescopes because they are hidden deep in the cloud, but the Spitzer's infrared instruments can see through the dust.

To a regular telescope, the Trifid Nebula looks like a dark wispy mist in front of a patch of brilliant light. It is about 5400 light-years away in the constellation Sagittarius. A light-year is about 10 trillion km, the distance light travels in a year.

In this same area, there is evidence of four clots of dark dust, known as cores, that are characteristic of places where stars form. Astronomers previously believed these dark areas were not yet ripe for star formations, but Spitzer's infrared observations showed massive stars taking shape there.

"With Spitzer, it's like we have ultrasound for stars," said Jeonghee Rho, an astronomer at the California Institute of Technology who headed this investigation.

Stellar embryos develop so quickly in these dark regions that it is difficult to catch them before they become full-fledged stars, Rho said at a meeting of the American Astronomical Society.

Spitzer found 30 massive stellar embryos and 120 smaller newborn stars in the Trifid Nebula. Only 10 of the embryos were detected in the dark cores. The rest were scattered through the nebula's dusty lanes and bright clouds.

Eventually, the embryos will accumulate enough gas and dust to ignite and explode out of their cores, the astronomers said.

- REUTERS