Figure 1: Supernova Dust Factory in Galaxy M74
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| Figure 2: July 2004 |
Figure 3: January 2005 |
This image is the galaxy M74, as seen by Spitzer's infrared array camera.
The white box (see figure 1) to the left of the galaxy's center identifies
the location of the supernova remnant. In all the images, the blue dots
represent hot gas and stars. The galaxy's cool dust is shown in red.
Astronomers using NASA's Spitzer Space Telescope have spotted a "dust
factory" 30 million light-years away in the spiral galaxy M74. The factory
is located at the scene of a massive star's explosive death, or supernova.
While astronomers have suspected for years that supernovae could be
producers of cosmic dust particles, the technology to confirm this
suspicion has only recently become available.
The dust factory, also known as supernova SN 2003gd, is shown at the
center of the two small insets from Spitzer's infrared array camera. A
white arrow points to its exact location (see figure 1). The yellow-green
dot shown in the July 2004 inset (see figure 2) shows that the source's
temperature is warmer than the surrounding material. This is because newly
formed dust within the supernova is just starting to cool. By January
2005, the dust had cooled and completely faded from the camera's view
(see figure 3). However, it was still detected in January 2005 by another
instrument aboard Spitzer called the multiband imaging photometer. The
image from that instrument is not shown here.
The images are false-color, infrared composites, in which 3.6-micron light
is blue, 4.5-micron light is green, and 8-micron light is red.
