Tupan Caldera, a volcanic crater on Jupiter's moon Io, has a relatively cool area, possibly an island, in its center, as indicated by infrared imagery from NASA's Galileo spacecraft.

A thermal portrait of Tupan collected by the near-infrared mapping instrument on Galileo during an Oct. 16, 2001 flyby is presented on the right, beside a visible-light image from Galileo's camera for geographical context. The infrared image uses false color to indicate intensity of glowing at a wavelength of 4.7 microns. Reds and yellows indicate hotter regions; blues are cold.

The hottest areas correspond to the dark portions in the visible-light image and are probably hot lavas. The central region in the crater may be an island or a topographically high region. Parts of it are cold enough for sulfur-dioxide to condense.

Tupan, an active volcano on Io since at least 1996, was named for the Brazilian native god of thunder.

The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. Additional information about Galileo and its discoveries is available on the Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://galileo.jpl.nasa.gov/gallery/io.cfm.