Chandra Reveals X-Ray Flow In Horshoe Nebula

Steve Roy
Media Relations Dept.
Marshall Space Flight Center, Huntsville, AL

(256) 544-0034

Megan Watzke
Chandra X-ray Obs. Center, CfA, Cambridge, MA

(617) 496-7998

For release: 08-19-03

Photo release no.: 03-141

Chandra reveals X-ray flow in Horseshoe Nebula
[http://www1.msfc.nasa.gov/NEWSROOM/n...os03-141.html]

A new image from NASA's Chandra X-ray Observatory reveals hot gas flowing away
from massive young stars in the center of the Horseshoe Nebula, also known as
M17 or the Omega Nebula. A group of massive young stars responsible for the
activity in the nebula is located in the bright pink region near the center of
the image.

Chandra's resolving power enabled astronomers to separate the contribution of
these and other stars in the nebula from X-rays produced by the hot gas flow,
which is shown in red. Temperatures in the hot gas flow range from 1.5 million
degrees Celsius (2.7 million degrees Fahrenheit) to about 7 million degrees
Celsius (13 million degrees Fahrenheit). The blue color indicates areas where
stars are embedded in clouds of dust and gas that absorb low energy X-rays.

An infrared image of the Horseshoe Nebula reveals a cloud of much cooler gas and
dust shaped like a horseshoe that gives the nebula its name. The hot gas shown
by the Chandra image fits inside the cool gas cloud, and appears to have formed
the horseshoe shape by carving a cavity in the cool gas. This activity could
lead to the formation of new stars in the Horseshoe.

The stars in the Horseshoe Nebula are only about a million years old, so the
nebula is too young for one of its stars to have exploded as a supernova and
heated the gas. Collisions between high-speed winds of particles flowing away
from the massive stars could heat the gas, or the hot gas could be produced as
these winds collide with cool clouds to form bubbles of hot gas. This hot gas
appears to be flowing out of the Horseshoe like champagne flows out of a bottle
when the cork is removed, so it has been termed an "X-ray champagne flow."

A comparison with other young star clusters confirms that massive young stars
are responsible for hot gas clouds like the one seen in the Horseshoe Nebula.
The Arches cluster, which contains many massive young stars shows this type of
cloud, whereas the central regions of the Orion Nebula, which has few massive
young stars, does not.

NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra
program for the Office of Space Science, NASA Headquarters, Washington. Northrop
Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development
contractor for the observatory. The Smithsonian Astrophysical Observatory
controls science and flight operations from the Chandra X-ray Center in
Cambridge, Mass.

The image and additional information are available at:

http://chandra.harvard.edu
and
http://chandra.nasa.gov