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The Question
(Submitted December 19, 1996)
I am currently doing a research paper involving cosmic rays.
My question is what are the effects of cosmic radiation to
other stellar bodies? Or do stellar bodies affect the behavior
of cosmic rays? How do cosmic particles get accelerated to speeds
almost the speed of light?
The Answer
Cosmic rays generally have little effect on other stellar
bodies. The energy absorbed from a cosmic ray may be re-emitted
at a lower energy, but the effect is usually small.
Stellar bodies affect the trajectories of cosmic rays primarily
through their magnetic fields. However, the overall magnetic
field of the interstellar medium is generally more important.
The acceleration mechanism in one of the key issues in the
study of cosmic rays. It is generally believed that cosmic rays
are accelerated in the shocks which accompany supernova explosions.
Recent evidence for this has been detected in ROSAT data of the
supernova remnant SN1006. The paper describing this result appeared
in the journal Nature in 1995 (the full reference is Koyama et al,
Nature, 1995 vol 378, pp. 255-258). Cosmic rays may also be
accelerated by the strong magnetic fields associated with pulsars.
For further discussion about cosmic rays, you might also check
the book "High Energy Astrophysics" by Malcom S. Longair (2nd Edition,
1992, Cambridge). Volume 2 contains a discussion of acceleration
mechanisms. You may likely find articles at more of a lay person
level in back issues of Sky and Telescope or Scientific American.
I hope this is helpful.
Jim Lochner
for Imagine the Universe!
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