Enceladus 'E-15' Flyby: Doing Science With Orion's Belt
This Enceladus flyby featured an ultraviolet stellar occultation, in which two of the three stars that make up Orion’s belt appear behind the moon’s plumes. Scientists hope to understand the density, composition, and variability of the jets from these observations. Infrared instruments and cameras monitored activity on the moon.
From Cassini Significant Events 10/19/11 - 10/25/11
Science activities on the spacecraft this week began with Enceladus E-15 flyby observations as the suite of optical instruments observed the surface of the moon as well as its dramatic plume and jets. Half an hour before closest approach, the Ultraviolet Imaging Spectrograph (UVIS) took control of the spacecraft to observe two stars in Orion’s Belt, epsilon Ori and zeta Ori, as they passed behind the plume of Enceladus. This observation gave a measurement of the vertical structure in the plume, and will help in pinning down collimation of gas in the jets. Once the occultation was completed, the Composite Infrared Spectrometer (CIRS) observed the surface of Enceladus as the spacecraft receded from the moon. Observations continued when Enceladus was in eclipse, i.e., in Saturn’s shadow, which provided a good opportunity for CIRS to investigate how different parts of Enceladus cool down during the eclipse and warm up again once sunlight returns.
Latest Cassini Images of Enceladus on View - Oct. 19, 2011
Orion's Belt Lights Up Cassini's View of Enceladus -- Oct. 18, 2011