Hubble reveals star formation in Orion Nebula

In one of the most detailed astronomical images ever produced, the Hubble space telescope has offered an unprecedented look at the Orion Nebula where massive stars are forming.

The Orion Nebula is one of the most dramatic and photogenic celestial objects in astronomy. The new Hubble picture revealed large-scale structures never seen before, astronomers said on Wednesday.

The crisp image reveals a tapestry of star formation, from the dense pillars of gas and dust that may be the homes of fledgling stars to the hot, young stars that have just emerged.

In a mosaic containing a billion pixels, Hubble's Advanced Camera for Surveys (ACS) uncovered 3,000 stars of various sizes. Some of them have never been spied in visible light, and some are merely 1/100 the brightness of stars seen previously.

Among the stars are possible young brown dwarfs, the first time these objects have been seen in the Orion Nebula in visible light. Brown dwarfs are so-called "failed stars." These cool objects are too small to be ordinary stars because they cannot sustain nuclear fusion in their cores the way our Sun does.

Hubble also spotted for the first time a small population of possible binary brown dwarfs, two brown dwarfs orbiting each other. Comparing the characteristics of newborn stars and brown dwarfs in their natal environment provides unique information about how they form, astronomers said.

"This Hubble survey provides an extraordinary opportunity to study star formation," said Massimo Robberto of the Space Telescope Science Institute, leader of the observations.

"Our goal is to calculate the masses and ages for these young stars so that we can map their history and get a general census of the star formation in that region. We can then sort the stars by mass and age and look for trends."

Robberto presented this results on Jan. 11 at the 207th meeting of the American Astronomical Society.

The Orion Nebula is a perfect laboratory to study how stars are born because it sits 1,500 light-years away from the Earth, a relatively short distance within our 100,000 light-year wide galaxy.

Astronomers have a clear view into this crowded stellar "delivery room" because massive stars in the center of the nebula have blown out most of the dust and gas in which they formed, carving a cavity in the dark cloud.

"In this bowl of stars we see the entire star formation history of Orion printed into the features of the nebula: arcs, blobs, pillars, and rings of dust that resemble cigar smoke," Robberto said in a statement.

"Each one tells a story of stellar winds from young stars that impact the stellar environment and the material ejected from other stars. This is a typical star-forming environment. Our Sun was probably born 4.5 billion years ago in a cloud like this one."

Source: Xinhua