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Figure 1 Click on the image for QuickTime movie | Figure 2 Click on the image for larger view of forsterite |
This artist's concept illustrates how silicate crystals like those found
in comets can be created by an outburst from a growing star. The image
shows a young sun-like star encircled by its planet-forming disk of gas
and dust. The silicate that makes up most of the dust would have begun as
non-crystallized, amorphous particles.
Streams of material are seen spiraling from the disk onto the star
increasing its mass and causing the star to brighten and heat up
dramatically. The outburst causes temperatures to rise in the star's
surrounding disk.
The animation (figure 1) zooms into the disk to show close-ups of silicate
particles. When the disk warms from the star's outburst, the amorphous
particles of silicate melt. As they cool off, they transform into
forsterite (figure 2), a type of silicate crystal often found in comets in
our solar system.
In April 2008, NASA's Spitzer Space Telescope detected evidence of this
process taking place on the disk of a young sun-like star called EX Lupi.