W5:
Pillars of Star Formation
From NASA’s Astronomy
Picture of the Day
How
do stars form? Images of the star forming region W5 like
those in the infrared by
NASA's Wide Field Infrared Survey Explorer (WISE) satellite provide clear clues
with indications 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.
In
the featured scientifically-colored infrared
image, spectacular pillars, left
slowly evaporating from the hot outflowing gas, provide further visual
clues.
W5 is
also known as IC 1848, and together with IC 1805form a
complex region of star formation popularly dubbed the Heart and Soul Nebulas.
The 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.
Image Credit: WISE, IRSA, NASA; Processing & Copyright : Francesco
Antonucci
