{"id":14002,"date":"2017-12-13T07:02:24","date_gmt":"2017-12-13T06:02:24","guid":{"rendered":"http:\/\/karmaka.de\/?p=14002"},"modified":"2017-12-13T15:05:03","modified_gmt":"2017-12-13T14:05:03","slug":"search-for-sulfates-on-the-surface-of-ceres","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=14002","title":{"rendered":"Search for sulfates on the surface of Ceres"},"content":{"rendered":"<p>Bu, C., Rodriguez Lopez, G., Dukes, C. A., Ruesch, O., McFadden, L. A. and Li, J.-Y. <\/p>\n<p>Meteoritics &#038; Planetary Science. doi: 10.1111\/maps.13024<\/p>\n<p><a href=\"http:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/maps.13024\/full\" target=\"_blank\"><strong>LINK<\/strong><\/a><\/p>\n<p>&#8220;The formation of hydrated salts is an expected consequence of aqueous alteration of Main Belt objects, particularly for large, volatile-rich protoplanets like Ceres. Sulfates, present on water-bearing planetary bodies (e.g., Earth, Mars, and carbonaceous chondrite parent bodies) across the inner solar system, may contribute to Ceres\u2019 UV and IR spectral signature along with phyllosilicates and carbonates. We investigate the presence and stability of hydrated sulfates under Ceres\u2019 cryogenic, low-pressure environment and the consequent spectral effects, using UV\u2013Vis\u2013IR reflectance spectroscopy. H2O loss begins instantaneously with vacuum exposure, measured by the attenuation of spectral water absorption bands, and a phase transition from crystalline to amorphous is observed for MgSO4\u00b76H2O by X-ray powder diffraction. Long-term (>40 h), continuous exposure of MgSO4\u00b7nH2O (n = 0, 6, 7) to low pressure (10\u22123\u201310\u22126 Torr) causes material decomposition and strong UV absorption below 0.5 \u03bcm. Our measurements suggest that MgSO4\u00b76H2O grains (45\u201383 \u03bcm) dehydrate to 2% of the original 1.9 \u03bcm water band area over ~0.3 Ma at 200 K on Ceres and after ~42 Ma for 147 K. These rates, inferred from an Avrami dehydration model, preclude MgSO4\u00b76H2O as a component of Ceres\u2019 surface, although anhydrous and minimally hydrated sulfates may be present. A comparison between Ceres emissivity spectra and laboratory reflectance measurements over the infrared range (5\u201317 \u03bcm) suggests sulfates cannot be excluded from Ceres\u2019 mineralogy.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Bu, C., Rodriguez Lopez, G., Dukes, C. A., Ruesch, O., McFadden, L. A. and Li, J.-Y. Meteoritics &#038; Planetary Science. doi: 10.1111\/maps.13024 LINK &#8220;The formation of hydrated salts is an expected consequence of aqueous alteration&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[167,1700],"tags":[1868,3755,4321],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/14002"}],"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=14002"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/14002\/revisions"}],"predecessor-version":[{"id":14003,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/14002\/revisions\/14003"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=14002"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14002"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14002"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}