What looks like a red
butterfly in space is in reality a nursery for hundreds of baby stars, revealed
in this infrared image from NASA's Spitzer Space Telescope. Officially named
Westerhout 40 (W40), the butterfly is a nebula - a giant cloud of gas and dust
in space where new stars may form. The butterfly's two "wings" are giant
bubbles of hot, interstellar gas blowing from the hottest, most massive stars
in this region.
Besides being beautiful,
W40 exemplifies how the formation of stars results in the destruction of the
very clouds that helped create them. Inside giant clouds of gas and dust in
space, the force of gravity pulls material together into dense clumps.
Sometimes these clumps reach a critical density that allows stars to form at
their cores. Radiation and winds coming from the most massive stars in those
clouds - combined with the material spewed into space when those stars
eventually explode - sometimes form bubbles like those in W40. But these
processes also disperse the gas and dust, breaking up dense clumps and reducing
or halting new star formation.
The material that forms W40's
wings was ejected from a dense cluster of stars that lies between the wings in
the image. The hottest, most massive of these stars, W40 IRS 1a, lies near the
center of the star cluster. W40 is about 1,400 light-years from the Sun, about
the same distance as the well-known Orion nebula, although the two are almost
180 degrees apart in the sky. They are two of the nearest regions in which
massive stars - with masses upwards of 10 times that of the Sun - have been observed
to be forming.
Another cluster of stars,
named Serpens South, can be seen to the upper right of W40 in this image.
Although both Serpens South and the cluster at the heart of W40 are young in
astronomical terms (less than a few million years old), Serpens South is the
younger of the two. Its stars are still embedded within their cloud but will someday
break out to produce bubbles like those of W40. Spitzer has also produced a more detailed image of the Serpens South cluster.
A mosaic of Spitzer's observation of the W40 star-forming region was originally published as part of the Massive Young stellar clusters
Study in Infrared and X-rays (MYStIX) survey
of young stellar objects.
The Spitzer picture is
composed of four images taken with the telescope's Infrared Array Camera (IRAC)
during Spitzer's prime mission, in different wavelengths of infrared light:
3.6, 4.5, 5.8 and 8.0 ?m (shown as blue, green, orange and red). Organic
molecules made of carbon and hydrogen, called polycyclic aromatic hydrocarbons
(PAHs), are excited by interstellar radiation and become luminescent at
wavelengths near 8.0 microns, giving the nebula its reddish features. Stars are
brighter at the shorter wavelengths, giving them a blue tint. Some of the
youngest stars are surrounded by dusty disks of material, which glow with a
yellow or red hue.
The Jet Propulsion
Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission
for NASA's Science Mission Directorate in Washington. Science operations are
conducted at the Spitzer Science Center at Caltech in Pasadena. Space
operations are based at Lockheed Martin Space Systems in Littleton, Colorado.
Data are archived at the Infrared Science Archive housed at IPAC at Caltech.
Caltech manages JPL for NASA.
More information on Spitzer can be found at its website: http://www.spitzer.caltech.edu/
News Media Contact
Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.
626-808-2469
calla.e.cofield@jpl.nasa.gov
Source: JPL-Caltech/Images
