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Saturn's
Hot Spot
This
is the
sharpest
image of
Saturn's
temperature
emissions
taken from
the
ground; it
is a
mosaic of
35
individual
exposures
made at
the W.M.
Keck I
Observatory,
Mauna Kea,
Hawaii on
Feb. 4,
2004.
The images
to create
this
mosaic
were taken
with
infrared
radiation.
The mosaic
was taken
at a
wavelength
near 17.65
microns
and is
sensitive
to
temperatures
in
Saturn's
upper
troposphere.
The
prominent
hot spot
at the
bottom of
the image
is right
at
Saturn's
south
pole. The
warming of
the
southern
hemisphere
was
expected,
as Saturn
was just
past
southern
summer
solstice,
but the
abrupt
changes in
temperature
with
latitude
were not
expected.
The
tropospheric
temperature
increases
toward the
pole
abruptly
near 70
degrees
latitude
from 88 to
89 Kelvin
(-301 to
-299
degrees
Fahrenheit)
and then
to 91
Kelvin
(-296
degrees
Fahrenheit)
right at
the pole.
Ring
particles
are not at
a uniform
temperature
everywhere
in their
orbit
around
Saturn.
The ring
particles
are
orbiting
clockwise
in this
image.
Particles
are
coldest
just after
having
cooled
down in
Saturn's
shadow
(lower
left). As
they orbit
Saturn,
the
particles
increase
in
temperature
up to a
maximum
(lower
right)
just
before
passing
behind
Saturn
again in
shadow.
A small
section of
the ring
image is
missing
because of
incomplete
mosaic
coverage
during the
observing
sequence. |
