{"id":29595,"date":"2021-11-23T06:42:57","date_gmt":"2021-11-23T05:42:57","guid":{"rendered":"https:\/\/karmaka.de\/?p=29595"},"modified":"2021-12-16T18:11:19","modified_gmt":"2021-12-16T17:11:19","slug":"the-impact-of-asteroid-shapes-and-topographies-on-their-reflectance-spectroscopy","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=29595","title":{"rendered":"The impact of asteroid shapes and topographies on their reflectance spectroscopy<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>S.M. Potin, S. Dout\u00e9, B. Kugler, F. Forbes<\/p>\n\n\n\n<p>Accepted for publication in Icarus<\/p>\n\n\n\n<p><a href=\"https:\/\/arxiv.org\/pdf\/2111.11290\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p>Update (16 December 2021):   <a rel=\"noreferrer noopener\" href=\"https:\/\/www.sciencedirect.com\/science\/article\/abs\/pii\/S0019103521004498\" target=\"_blank\"><strong><a rel=\"noreferrer noopener\" href=\"https:\/\/www.sciencedirect.com\/science\/article\/abs\/pii\/S0019103521004498\" target=\"_blank\"><strong>LINK<\/strong><\/a><\/strong><\/a><\/p>\n\n\n\n<p>&#8220;Highlights<\/p>\n\n\n\n<p>\u2022 The spectral bidirectional reflectance of two reference surfaces is measured in the laboratory.<br>\u2022 Unresolved spectral observations of asteroidal bodies are simulated.<br>\u2022 The shape and surface topography induce variations of local observation angles.<br>\u2022 Phase curves of unresolved simulated bodies differ from laboratory measurements.<br>\u2022 The reflectance and spectral slope are the most impacted parameters.&#8221;<\/p>\n\n\n\n<p class=\"justify-text\">&#8220;We report the comparison between unresolved reflectance spectroscopy of Solar System small bodies and laboratory measurements on reference surfaces. We measure the bidirectional reflectance spectroscopy of a powder of howardite and a sublimation residue composed of a Ceres analogue. The spectra are then inverted using the Hapke semi-empirical physical model and the MRTLS parametric model to be able to simulate the reflectance of the surfaces under any geometrical configuration needed. We note that both models enable an accurate rendering of the reflectance spectroscopy, but the MRTLS model adds less noise on the spectra compared to the Hapke model. Using the parameters resulting from the inversions, we simulate two spherical bodies and the small bodies (1)Ceres and (4)Vesta whose surfaces are homogeneously covered with the Ceres analogue and powder of howardite respectively. We simulate various scenarios of illumination and spectroscopic observations, spot-pointing and fly-bys, of these small bodies for phases angles between 6\u00b0 and 135\u00b0. The unresolved reflectance spectroscopy of the simulated bodies is retrieved from the resulting images, and compared to the reflectance spectroscopy of the reference surface. Our results show that the photometric phase curves of the simulated bodies are different from the reference surfaces because of the variations of the local incidence and emergence angles due to the shape and topography of the surface. We observe the maximum differences at wide phase angles with the various simulated observations of (4)Vesta due to its high surface topography. Finally, we highlight the differences in the spectral parameters derived from the unresolved observations at 30\u00b0 with laboratory measurements acquired under a single geometrical configuration.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>S.M. Potin, S. Dout\u00e9, B. Kugler, F. Forbes Accepted for publication in Icarus PDF (OPEN ACCESS) Update (16 December 2021): LINK &#8220;Highlights \u2022 The spectral bidirectional reflectance of two reference surfaces is measured in the&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77,167,34,130,186],"tags":[1771,1822,1479,1480],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/29595"}],"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=29595"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/29595\/revisions"}],"predecessor-version":[{"id":29762,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/29595\/revisions\/29762"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=29595"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=29595"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=29595"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}