W5: Pillars of Star Formation
Image Credit & Copyright: Lori Allen, Xavier Koenig (Harvard-Smithsonian CfA) et al., JPL-Caltech, NASA Explanation: How do stars form? A study of star forming region
W5 by the sun-orbiting
Spitzer Space Telescope provides clear clues by recording that massive stars near the center of empty cavities are older than stars near the edges. A likely reason for this is that the older stars in the center are actually
triggering the formation of the younger edge stars. The triggered
star formation occurs when hot outflowing gas compresses cooler gas into
knots dense enough to gravitationally contract into stars.
Spectacular pillars, left slowly evaporating from the hot outflowing gas, provide further
visual clues. In the
above scientifically-colored
infrared image, red indicates heated
dust, while white and green indicate particularly dense gas clouds.
W5 is also known as
IC 1848, and
together with IC 1805 form a complex region of star formation popularly dubbed the
Heart and
Soul Nebulas. The
above image highlights a part of W5 spanning about 2,000
light years that is rich in
star forming pillars. W5 lies about 6,500 light years away toward the
constellation of
Cassiopeia.
link:
November 20
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