3-Panel Version
Figure 1
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Visible (DSS)
Figure 2 |
Infrared (IRAC)
Figure 3 |
Infrared (IRAC + MIPS)
Figure 4 |
For the universe's biggest stars, even death is a show. Massive stars
typically end their lives in explosive cataclysms, or supernovae,
flinging abundant amounts of hot gas and radiation into outer space.
Remnants of these dramatic deaths can linger for thousands of years and
be easily detected by professional astronomers.
However, not all stars like attention. Thirty thousand light-years away in
the Cepheus constellation, astronomers think they've found a massive star
whose death barely made a peep. Remnants of this shy star's supernova
would have gone completely unnoticed if the super-sensitive eyes of NASA's
Spitzer Space Telescope hadn't accidentally stumbled upon it.
These three panels (figure 1) illustrate just how shy this star is.
Unlike most supernova remnants, which are detectable at a variety of
wavelengths ranging from radio to X-rays, this source only shows up in
mid-infrared images taken by Spitzer's multiband imaging photometer. The
remnant can be seen as a red-orange blob at the center of the picture
(figure 4).
Although the visible-light (figure 2) and near-infrared (figure 3) images
capture the exact same region of space, the source is completely invisible
in both pictures. Astronomers suspect that the remnant's elusiveness is
due to its location, away from our Milky Way galaxy's dusty main disk,
which contains most of the galaxy's stars. A supernova is most noticeable
when the material expelled during the star's furious death throes
violently collides with surrounding dust. Since the shy star sits away
from the galaxy's dusty and crowded disk, the hot gas and radiation it
flung into space had little surrounding material to crash into. Thus, it
is largely invisible at most wavelengths.
Spitzer's multiband imaging photometer did not need dust to see the
remnant. The mid-infrared instrument was able to directly detect the
oxygen-rich gas from the supernova's explosive death throes.
The visible-light (figure 2) image is a three-color composite of data from
the California Institute of Technology's Digitized Sky Survey. In this
image, light with a wavelength of 0.44 microns is represented as blue,
0.55-micron light is green, and 0.9-micron light is red.
The near-infrared (figure 3 ) image is a two-color composite of data from
Spitzer's infrared array camera. In this image, starlight captured at 4.5
microns is represented in blue, and 8-micron light from dust is green. The
far-infrared image (figure 4) combines the infrared array camera data
with the multiband imaging photometer data, which show light of 24 microns
in red.
