LINK<\/strong><\/a><\/p>\n\n\n\n“Highlights<\/p>\n\n\n\n
\u2022 We use a Bayesian approach to derive the photometric parameters from NIRS3 data.
\u2022 Ryugu is to first order homogeneous though some slight heterogeneity can be noticed.
\u2022 The SSA is derived and mapped to investigate potential albedo variations.
\u2022 The presence of darker areas linked to geomorphological features is established.
\u2022 These areas tend to have a deeper 2.72 \u03bcm band compared to their surroundings.”<\/p>\n\n\n\n
“The type C asteroid Ryugu has been visited by the JAXA Hayabusa2 mission, a first for a primitive asteroid in the Solar System exploration. Samples have been collected at its surface by the spacecraft and are now on their way back to Earth. The surface of Ryugu has also been observed both in the visible and infrared wavelengths with the objective of characterizing its properties at a global scale. Here, we report on the albedo and spectro-photometric properties of Ryugu as derived from the NIRS3 IR spectrometer. Thanks to an innovative technique based on a Bayesian approach, we retrieved the Hapke photometric parameters from multi-geometric NIRS3 observations over the NIR spectral range and different areas of Ryugu, including the first collection site. Results reveal an overall spatial homogeneity of the photometric parameters, though some small variations can be highlighted. A new photometric correction was derived and applied to NIRS3 data. Reflectance spatial heterogeneity was quantitatively investigated, in particular by deriving and mapping the single scattering albedo (SSA) at various spatial scales. This parameter could be derived with confidence on about one fourth of Ryugu\u2019s surface, especially around the equatorial region and the southern middle latitudes. Although Ryugu is to first order homogenous with a typical SSA of 0.045\u20130.050, we demonstrate with a local-scale photometric correction (1) the presence of a large \u201cbright\u201d area between ~ 190\u00b0 E and ~ 290\u00b0 E longitude around the equator and the southern middle latitudes, and (2) the presence of darker areas with a clear connection to geomorphological features. We show here that these darker regions tend to have a slightly deeper 2.72 \u03bcm feature, at least compared to the surrounding areas, which can be explained by an enrichment of the top-surface in dark fines coupled to hydrated phases. Some spatial variability observed in the coupling between the SSA at 1.89 \u03bcm and the 2.72 \u03bcm feature also suggests that Ryugu exhibits some (slight) heterogeneity in its building blocks.”<\/p>\n","protected":false},"excerpt":{"rendered":"
C. Pilorget, J. Fernando, L. Riu, K. Kitazato, T. Iwata IcarusIn Press, Journal Pre-proof, Available online 29 September 2020 LINK “Highlights \u2022 We use a Bayesian approach to derive the photometric parameters from NIRS3 data.\u2022…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77,2350,2243,181],"tags":[1768,1854,2244,4684],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/23922"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=23922"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/23922\/revisions"}],"predecessor-version":[{"id":23923,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/23922\/revisions\/23923"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=23922"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=23922"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=23922"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}