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Saturn:
X-rays from Saturn Pose Puzzles
Chandra's image of Saturn held some surprises for the observers. First,
Saturn's 90 megawatts of X-radiation is concentrated near the equator.
This is different from a similar gaseous giant planet, Jupiter, where
the most intense X-rays are associated with the strong magnetic field
near its poles.
Saturn's X-ray spectrum, or the distribution of its X-rays according to
energy, was found to be similar to that of X-rays from the Sun. This
indicates that Saturn's X-radiation is due to the reflection of solar
X-rays by Saturn's atmosphere. The intensity of these reflected X-rays
was unexpectedly strong.
Further observations should help clarify the nature of Saturn's
X-radiation, and determine whether Saturn's magnetic polar regions ever
flare up in X-rays, as do Jupiter's. The features outside of Saturn's
disk in the X-ray image are instrumental artifacts or "noise".
The optical image of Saturn is also due to the reflection of light from
the Sun - visible wavelength light in this case - but the optical and
X-ray images obviously have dramatic differences. The optical image is
much brighter, and shows the beautiful ring structures, which were not
detected in X-rays. This is because the Sun emits about a million times
more power in visible light than in X-rays, and X-rays reflect much less
efficiently from Saturn's atmosphere and rings.
| Fast Facts for Saturn: |
| Credit |
X-ray: NASA/U. Hamburg/J.Ness et al; Optical: NASA/STScI |
| Scale |
Each panel is 42 arcsec per side;
the disk of Saturn is 17.5 arcsec in diameter |
| Category |
Solar System |
| Observation Date |
April 14-15, 2003 |
| Observation Time |
20 hours |
| Obs. ID |
3725, 4433 |
| Color Code |
Energy (Red 0.4 - 0.6 keV; Green 0.6 - 0.8 keV; Blue 0.8 - 1.0 keV) |
| Instrument |
ACIS |
| Reference |
J. Ness et al. 2004 Astronomy & Astrophysics (March 8 issue) also astro-ph/0401270 |
| Distance Estimate |
At time of observation: 890 million miles (1.4 billion kilometers) |
| Release Date |
March 8, 2004 |
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