Media Information

 
 
 
Collection:
NASA Cassini-Huygens Collection
Title:
Iapetus Thermal Radiation Image
Description:
Iapetus Thermal Radiation Image
Full Description:
This image of the infrared heat radiation from Saturn's moon Iapetus was obtained by the Cassini composite infrared spectrometer instrument 16 hours before Cassini's closest approach to this mysterious moon, on December 31, 2004. The thermal radiation is shown as both a grayscale image, equivalent to what we would see if our eyes were sensitive to infrared wavelengths near 15 microns, and as a color-coded temperature map. A previously-released mosaic obtained by Cassini's imaging camera shortly before the composite infrared spectrometer observation, with similar scale and orientation, is also shown for comparison.

Temperatures reach nearly 130 Kelvin (-226 Fahrenheit) at noon on the equator on the dark material that covers most of this side of Iapetus, making high noon on Iapetus's dark side probably the warmest places in the Saturn system. This is much warmer than temperatures on another Saturnian moon, Phoebe, measured by composite infrared spectrometer in June 2004. Those Phoebe temperature measurements peaked near 112 Kelvin (-258 Fahrenheit), because though Phoebe is almost as dark as Iapetus's dark material and absorbs nearly as much sunlight, Phoebe rotates much more quickly (once every 9 hours, compared to 79 days for Iapetus). That means the surface has less time to heat up during the day. Temperatures on Iapetus's bright material are much colder, peaking near 100 Kelvin (-280 Fahrenheit), both because the bright material absorbs less sunlight and because it is further from the equator on this side of Iapetus. Temperatures in the large crater near the center of the disc are slightly different from those in surrounding areas, because sloping surfaces within the crater are warmer where they are tilted towards the Sun and cooler when tilted away from the Sun.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. For more information about the Cassini-Huygens mission visit, http://saturn.jpl.n…and the instrument team's home page, http://cirs.gsfc.na…

*Credit*: NASA/JPL/GSFC
Date:
January 10, 2005
Keywords:
images
Keywords:
cassini
Keywords:
moons
Keywords:
iapetus
facet_what:
Saturn
facet_what:
Cassini
facet_what:
Cassini-Huygens
facet_what:
Huygens Probe
facet_what:
Moon
facet_what:
Cassini Orbiter
facet_what:
Crater
facet_what:
Sun
facet_what:
Iapetus
facet_what:
Spectrometer
facet_what:
Infrared Spectrometer
facet_what:
Composite Infrared Spectrometer
facet_where:
Saturn
facet_where:
Jet Propulsion Laboratory
facet_where:
California
facet_where:
Washington
facet_where:
Jet Propulsion Laboratory (JPL)
facet_where:
Washington, D.C.
facet_where:
Goddard Space Flight Center (GSFC)
facet_when:
June 2004
facet_when:
January 10, 2005
facet_when:
December 31, 2004
facet_when_year:
2005
facet_when_year:
2004
UID:
SPD-SATRN-1281
original url:

Iapetus Thermal Radiation Image