Predicted Antenna Temperatures Measured by REX/New Horizons During The Pluto’s FlybyProbing the sub-surface in Microwave

• Main Authors: Leyrat, Cédric, Le Gall, Alice, Lorenz, Ralph, Boomi, Shadi
• Other Authors: Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Johns Hopkins University (JHU)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2017
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; [SDU]Sciences of the Universe [physics]; South Pole; South pole
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-01665849

International audience The Pluto dwarf planet was observed in details in July 2015 by the New Horizons spacecraft (NASA) during a close-targeted flyby which reavealed surprising and fascinating landscapes with a variety of albedo and chemical composition over the surface. During the flyby, the REX microwave instrument was activated in order to measure the antenna temperature while the beam crossed Pluto’s surface. In particular, 3 scans were performed, the first two during few tens of seconds when both the day and night side of Pluto were observed, including the South pole and the last one during an occultation with Earth. We present here predited antenna temperatures considering the known and assumed variations of thermal and electrical properties of the Pluto’s sub-surface. Each scan allow to observe thermal radiation at 4.2 cm wavelength of the surface and subsurface of Pluto, at different locations (latitudes / longitudes). Using a seasonnal thermal model that considers the measured Bond albedo and type of ice, we have modeled the Brightness temperatures that were measured by REX, for different amount of porosity (or thermal inertia). This modeling uses a seasonally-forced thermal model and an emissivity model in the case of circular polarized observations. An antenna temperature if then retrieved assuming a beam pattern for REX. We present here how the antenna temperatures vary with the porosity of the ices obseved.