Chandra Examines Jupiter During New Horizons Approach (Forwarded)

Megan Watzke
Chandra X-ray Center, Cambridge, Mass.
(Phone: 617/496-7998)

March 1, 2007

Chandra Examines Jupiter During New Horizons Approach
[http://chandra.harvard.edu/photo/2007/jupiter/]

On February 28, 2007, NASA's New Horizons spacecraft made its closest
approach to Jupiter on its ultimate journey to Pluto. This flyby gave
scientists a unique opportunity to study Jupiter using the package of
instruments available on New Horizons, while coordinating observations
from both space- and ground-based telescopes including NASA's Chandra
X-ray Observatory.

In preparation for New Horizon's approach of Jupiter, Chandra took 5-hour
exposures of Jupiter on February 8, 10, and 24th. In this new composite
image, data from those separate Chandra's observations were combined, and
then superimposed on the latest image of Jupiter from the Hubble Space
Telescope.

The purpose of the Chandra observations is to study the powerful X-ray
auroras observed near the poles of Jupiter. These are thought to be caused
by the interaction of sulfur and oxygen ions in the outer regions of the
Jovian magnetic field with particles flowing away from the Sun in the
so-called solar wind. Scientists would like to better understand the
details of this process, which produces auroras up to a thousand times
more powerful than similar auroras seen on Earth.

Following closest approach on the 28th, Chandra will continue to observe
Jupiter over the next few weeks. New Horizons will take an unusual
trajectory past Jupiter that takes it directly down the so-called magnetic
tail of the planet, a region where no spacecraft has gone before. The
sulfur and oxygen particles that dominate Jupiter's magnetosphere and
originate in Io's volcanoes are eventually lost down this magnetic tail.
One goal of the Chandra observations is to see if any of the X-ray auroral
emissions are related to this process.

By combining Chandra observations with the New Horizons data, plus
ultraviolet information from NASA's Hubble Space Telescope and FUSE
satellite, and optical data from ground-based telescopes, astronomers hope
to get a more complete picture of Jupiter's complicated system of
particles and magnetic fields and energetic particles. In the weeks and
months to come, astronomers will undertake detailed analysis of this
bounty of data.