Resolving Enceladus thermal emission at the 10s of meters scale along Baghdad Sulcus using Cassini CIRS
Abstract
On 14th April 2012 Cassini executed one of its closest flyby to the South Pole of Enceladus with the primary goal to study the moon’s gravity. During this flyby the Composite InfraRed Spectrometer (CIRS) was orientated such that its three focal planes were dragged across Baghdad sulcus. The instrument was specifically configured to record interferograms with 52 seconds duration. CIRS focal plane 1 (17 to 1000 µm) single circular detector provided a spatial resolution of about 300 meters. CIRS focal plane 3 and 4 (9 to 17 µm and 7 to 9 µm) are 2 1x10 detectors arrays. Both arrays were used in pair mode leading to 5 elements per focal plane and a resolution of about 43 meters across track.The ground-track speed was so fast during this observation that this was enough time to observe the entire South Polar Region in a single integration. The thermal sources were passed over so rapidly that it is not possible to reconstruct a spectrum from the resulting interferogram, instead features were created in the interferogram whenever the scene temperature changed. The signature of these features was also altered by bit trimming and band-pass filter convolution. To enable interpretation of the interferograms we developed an innovative new approach that included the development of new instrument models, modification of the flight software and multiple in flight validation experiments. Our preliminary results show temperature variability of the tiger stripes at 10s meters scale along track, providing a constraint on the distribution and temperature profile of Enceladus’ endogenic sources.A similar methodology will be used for the penultimate targeted Enceladus flyby in Oct 28th 2015 and we aim to also present our preliminary analysis of the results from this encounter
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #47
- Pub Date:
- November 2015
- Bibcode:
- 2015DPS....4741001G