New Observations Show Sun-like Star In Earliest Stage Of Development (Forwarded)

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University of Colorado-Boulder
Boulder, Colorado

Contact:
Jeffrey Linsky, (303) 492-7838
Jim Scott, (303) 492-3114

Feb. 15, 2007

New Observations Show Sun-like Star In Earliest Stage Of Development

Members of a research team led by the University of Colorado at Boulder have
used NASA's Chandra X-ray Observatory to peer at the embryo of an infant
star in the nearby Eagle Nebula, which they believe may someday develop into
a virtual twin of Earth's sun.

The object, known as an evaporating gas globule, or EGG, has the same mass
as the sun and appears to be evolving in a violent environment much like the
one believed to have produced Earth's sun, said researcher Jeffrey Linsky of
JILA, a joint institute of CU-Boulder and the National Institute of
Standards and Technology. Located in a region called the Pillars of Creation
in the Eagle Nebula roughly 7,000 light-years from Earth, the object --
dubbed E42 -- is thought to be in the earliest stage astronomers have ever
detected a star like the sun, said Linsky.

A new image of the Pillars of Creation, consisting of a Hubble Space
Telescope image overlaid with Chandra X-ray data, was released Feb. 15 by
the Chandra X-ray Observatory Center in Cambridge, Mass. The image
[http://chandra.harvard.edu/photo/2007/m16/], which shows red, green and
blue dots representing low-, medium- and high-energy X-rays, indicates there
are relatively few X-ray sources in the pillars and suggests the Eagle
Nebula is past its star-forming prime, said Linsky.

Linsky and colleagues from West Chester University in Pennsylvania, the
University of Exeter in England and the University of Arizona analyzed
visual and infrared emissions from the pillars to identify E42, the sun-like
proto-star. E42 is located in the left pillar on the right edge of a node
jutting out to the right about two-thirds of the way down the pillar.

"We think this is a very, very early version of our own sun," said Linsky.

E42 is one of 73 EGGs discovered in the Pillars of Creation in 1996 with the
Hubble Space Telescope by Arizona State University astronomer Jeff Hester
and his team. While 11 of the EGGs have been determined to contain infant
stellar objects, only four are massive enough to form a star. Of those, E42
is the only one that has a sun-sized mass, said Linsky.

"The four proto-stars that we have identified on the edges of the pillars
are probably the youngest stars ever imaged by astronomers," Linsky said

While Linsky and his team used Chandra to zero in on more than 1,100 hotter,
more mature stars in the Eagle Nebula, neither E42 nor the other three EGGs
believed massive enough to form stars were observed to be emitting any
X-rays, he said. "The results indicate young, evolving stars like E42 have
not yet developed the magnetic structures needed to produce X-rays," he
said.

Earth's sun is thought to have formed some 5 billion years ago after clouds
of dust and gas were seared by ultraviolet radiation and pounded by
shockwaves from one or more supernovae explosions, Linsky said. "The sun was
likely born in a region like the Pillars of Creation because the chemical
abundances in the solar system indicate that a supernova occurred nearby and
contributed its heavy elements to the gas of which the sun and the planets
formed."

A January 2007 study by an astronomy team from France suggested the pillars
were toppled some 6,000 years ago by a nearby supernova explosion, as
evidenced by a glowing cloud of scorched dust adjacent to the pillars. Since
the pillars are roughly 7,000 light years away, the French team contends
they will still be visible from Earth as "ghost images" for another thousand
years or so.

"My guess is that the shock wave from the supernova may have been far enough
away so that E42 and some of the other stars may have survived," said
Linsky. "But I guess we will have to wait another thousand years or so to
get the answer."

Other astronomy team members collaborating with Linsky included Marc Gagne
and Anne Mytyk of West Chester University, Mark McCaughrean of the
University of Exeter and Morten Andersen of the University of Arizona. A
paper on the subject was published in the Jan. 1 issue of the Astrophysical
Journal. The orbiting Chandra X-Ray Observatory was deployed by NASA aboard
a space shuttle and boosted into high Earth orbit in July 1999 to study the
origin, evolution and destiny of the universe.