Figure 2: Schematic drawing of how to measure the background light. By measuring the difference between the light from the eclipsed satellite and the surrounding sky data, one would obtain the background light information, if the eclipsed satellite is completely dark. It turned out that there is still a faint light reflected off from the satellite during the eclipse. (Credit: NAOJ/JAXA/Tohoku University)
- Observations of Jupiter's upper atmosphere were conducted by the Galileo spacecraft, and by "occultation" of microwaves from field stars or spacecraft located behind Jupiter. However, opportunities to observe these events are rare and limited, thus the observations of the Galilean satellite eclipses are a unique method to study Jupiter's upper atmosphere.
- Transmitted light through the planetary atmosphere was observed by the occultation methods described in (*1) and the Venus transit. However, they are very rare events, too.
"Near-infrared Brightness of the Galilean Satellites Eclipsed in Jovian Shadow: A New Technique to Investigate Jovian Upper Atmosphere"
K. Tsumura (1,2), K. Arimatsu (2,3), E. Egami (4), Y. Hayano (5), C. Honda (6), J. Kimura (7), K. Kuramoto (8), S. Matsuura (2), Y. Minowa (5), K. Nakajima (9), T. Nakamoto (10), M. Shirahata (2, 11), J. Surace (12), Y. Takahash i(8), and T. Wada (2)