NASA's
Spitzer Space Telescope has captured a new, infrared view of the choppy
star-making cloud called M17, or the Swan nebula.
The cloud,
located about 6,000 light-years away in the constellation Sagittarius, is
dominated by a central group of massive stars the most massive stars in the
region. These central stars give off intense flows of expanding gas, which rush
like rivers against dense piles of material, carving out the deep pocket at
center of the picture.
Winds from
the region's other massive stars push back against these oncoming rivers,
creating bow shocks like those that pile up in front of speeding boats.
Three of
these bow shocks are nestled in the upper left side of the central cavity, but
are difficult to spot in this view. They are composed of compressed gas in
addition to dust that glows at infrared wavelengths Spitzer can see. The
smiley-shaped bow shocks curve away from the stellar winds of the central
massive stars.
In the
image, dust is red, hot gas is green and white is where gas and dust
intermingle. Foreground and background stars appear scattered through the
image.