WWW.ASTRONOMY.COM 25- Delicate tendrils of
dust glow brightly in the
infrared as the massive
star Zeta Ophiuchi
approaches. As Zeta —
the luminous blue star at
center — plows forward
(to the left) at about
53,000 mph (86,000 km/h),
its powerful stellar winds
create a bow shock in the
surrounding dust, similar
to the ripples that form in
front of a moving ship’s
bow. The red hues arise
from the warmest, most
compressed dust. NASA/
JPL-CALTECH - When a massive star
dies, it explodes as a
supernova and seeds
the galaxy with heavy
elements that one day
may find their way into
future generations of
stars and planets. This
image of the supernova
remnant Cassiopeia A
blends observations from
three of NASA’s Great
Observatories: Spitzer
infrared data (in red)
highlight warm dust in the
outer shell; Hubble visible-
light observations (yellow)
reveal delicate filaments
of hot gas; and Chandra
X-ray data (green and
blue) expose the hottest
gases. NASA/JPL-CALTECH/O. KRAUSE
(STEWARD OBSERVATORY) - Once the Sun exhausts
its nuclear fuel in another
5 billion years or so, it will
puff off its outer layers
and create a planetary
nebula, perhaps similar
to the Helix Nebula (NGC
- in Aquarius. When
viewed in the infrared, the
Helix’s expanding outer
layers shine brightest
at shorter wavelengths
(shown as blue and
green), while a central
disk of dust and the final
layers ejected by the
dying star glow at longer
wavelengths (red). NASA/JPL-
CALTECH/K. SU (UNIVERSITY OF ARIZONA)
- The Serpens South star
cluster harbors some 50
young stars. Of these, 35
are protostars — objects
that have not yet started
fusing hydrogen and are
still collecting matter
from the surrounding
molecular cloud. The
cluster members appear
as a tightly packed group
of green, yellow, and
orange stars at the center
of this Spitzer infrared
image. NASA/JPL-CALTECH/L. ALLEN
(HARVARD-SMITHSONIAN CfA)/GOULD’S
BELT LEGACY TEAM
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