{"id":27862,"date":"2021-05-25T09:27:07","date_gmt":"2021-05-25T07:27:07","guid":{"rendered":"https:\/\/karmaka.de\/?p=27862"},"modified":"2021-08-06T15:10:50","modified_gmt":"2021-08-06T13:10:50","slug":"the-surface-of-16-psyche-from-thermal-emission-and-polarization-mapping","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=27862","title":{"rendered":"The Surface of (16) Psyche from Thermal Emission and Polarization Mapping<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Katherine de Kleer, Saverio Cambioni, Michael Shepard<\/p>\n\n\n\n<p>To be published in Planetary Science Journal<\/p>\n\n\n\n<p><a rel=\"noreferrer noopener\" href=\"https:\/\/arxiv.org\/pdf\/2105.11372.pdf\" target=\"_blank\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p>Update (6 August 2021): The Planetary Science Journal, Volume 2, Number 4<\/p>\n\n\n\n<p><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/PSJ\/ac01ec\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/PSJ\/ac01ec\/pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;The asteroid (16) Psyche is the largest of the M-type asteroids, which have been hypothesized to be the cores of disrupted planetesimals and the parent bodies of the iron meteorites. While recent evidence has collected against a pure metal composition for Psyche, its spectrum and radar properties remain anomalous. We observed (16) Psyche in thermal emission with the Atacama Large (sub-)Millimeter Array (ALMA) at a resolution of 30 km over 2\/3 of its rotation. The diurnal temperature variations are at the \u223c10 K level over most of the surface and are best fit by a smooth surface with a thermal inertia of 280\u00b1100 J m\u22122 K\u22121 s\u22121\/2. We measure a millimeter emissivity of 0.61\u00b10.02, which we interpret via a model that treats the surface as a porous mixture of silicates and metals, where the latter may take the form of iron sulfides\/oxides or alternatively as conducting metallic inclusions. The emissivity indicates a metal content of no less than 20\\% and potentially much higher, but the polarized emission that should be present for a surface with \u226520\\% metal content is almost completely absent. This requires a highly scattering surface, which may be due to the presence of reflective metallic inclusions. If such is the case, a consequence is that metal-rich asteroids may produce less polarized emission than metal-poor asteroids, exactly the opposite prediction from standard theory, arising from the dominance of scattering over the bulk material properties.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Katherine de Kleer, Saverio Cambioni, Michael Shepard To be published in Planetary Science Journal PDF (OPEN ACCESS) Update (6 August 2021): The Planetary Science Journal, Volume 2, Number 4 LINK (OPEN ACCESS)PDF (OPEN ACCESS) &#8220;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":[77,2495,5891,181,1184],"tags":[2496,1854,1771,4515,1019,2298],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/27862"}],"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=27862"}],"version-history":[{"count":3,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/27862\/revisions"}],"predecessor-version":[{"id":28558,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/27862\/revisions\/28558"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=27862"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=27862"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=27862"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}