{"id":31326,"date":"2022-10-04T18:32:25","date_gmt":"2022-10-04T16:32:25","guid":{"rendered":"https:\/\/karmaka.de\/?p=31326"},"modified":"2022-10-04T18:32:26","modified_gmt":"2022-10-04T16:32:26","slug":"physical-characterization-of-near-earth-asteroid-52768-1998-or2-evidence-of-shock-darkening-impact-melt","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=31326","title":{"rendered":"Physical Characterization of Near-Earth Asteroid (52768) 1998 OR2: Evidence of Shock Darkening\/Impact Melt<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Adam Battle, Vishnu Reddy, Juan A. Sanchez, Benjamin Sharkey, Neil Pearson and Bryn Bowen<\/p>\n\n\n\n<p>The Planetary Science Journal, Volume 3, Number 9<\/p>\n\n\n\n<p><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/PSJ\/ac7223\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/PSJ\/ac7223\/pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;We conducted photometric and spectroscopic characterization of near-Earth asteroid (52768) 1998 OR2 during a close approach to Earth in 2020 April. Our photometric measurements confirm the rotation period of the asteroid to be 4.126 \u00b1 0.179 hr, consistent with the previously published value of 4.112 \u00b1 0.001 hr. By combining our visible spectroscopic measurements (0.45\u20130.93\u03bcm) with archival MITHNEOS near-infrared spectra (0.78\u20132.49\u03bcm), we classify the asteroid as an Xn-type in the Bus\u2013DeMeo taxonomy. The combined spectrum shows two weak absorption bands: Band I at 0.926 \u00b1 0.003\u03bcm and Band II at 2.07 \u00b1 0.02\u03bcm, with band depths of 4.5% \u00b1 0.15% and 4.0% \u00b1 0.21%, respectively. The band area ratio is 1.13 \u00b1 0.05. These spectral band parameters plot at the tip of the S(IV) region of the Gaffey S-asteroid subtypes plot, suggesting an affinity to ordinary chondrite meteorites. We calculated the chemistry of olivine and pyroxene using the Band I center to be 20.1 \u00b1 2.3 mol% fayalite and 18.2 \u00b1 1.5 mol% ferrosilite, consistent with H-chondrites. Principal component analysis of 1998 OR2&#8217;s combined visible\u2013near-IR spectrum falls on the C\/X-complex side of the\u03b1-line, near the end of the shock-darkening trend, consistent with its weak absorption bands (band depth &lt;5%). We use an areal mixing model with lab measurements of the shock-darkened H5 chondrite, Chergach, to constrain the amount of shock-darkened material on the asteroid&#8217;s surface at \u223c63% dark lithology and \u223c37% light lithology.We conducted photometric and spectroscopic characterization of near-Earth asteroid (52768) 1998 OR2 during a close approach to Earth in 2020 April. Our photometric measurements confirm the rotation period of the asteroid to be 4.126 \u00b1 0.179 hr, consistent with the previously published value of 4.112 \u00b1 0.001 hr. By combining our visible spectroscopic measurements (0.45\u20130.93\u03bcm) with archival MITHNEOS near-infrared spectra (0.78\u20132.49\u03bcm), we classify the asteroid as an Xn-type in the Bus\u2013DeMeo taxonomy. The combined spectrum shows two weak absorption bands: Band I at 0.926 \u00b1 0.003\u03bcm and Band II at 2.07 \u00b1 0.02\u03bcm, with band depths of 4.5% \u00b1 0.15% and 4.0% \u00b1 0.21%, respectively. The band area ratio is 1.13 \u00b1 0.05. These spectral band parameters plot at the tip of the S(IV) region of the Gaffey S-asteroid subtypes plot, suggesting an affinity to ordinary chondrite meteorites. We calculated the chemistry of olivine and pyroxene using the Band I center to be 20.1 \u00b1 2.3 mol% fayalite and 18.2 \u00b1 1.5 mol% ferrosilite, consistent with H-chondrites. Principal component analysis of 1998 OR2&#8217;s combined visible\u2013near-IR spectrum falls on the C\/X-complex side of the\u03b1-line, near the end of the shock-darkening trend, consistent with its weak absorption bands (band depth &lt;5%). We use an areal mixing model with lab measurements of the shock-darkened H5 chondrite, Chergach, to constrain the amount of shock-darkened material on the asteroid&#8217;s surface at \u223c63% dark lithology and \u223c37% light lithology.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Adam Battle, Vishnu Reddy, Juan A. Sanchez, Benjamin Sharkey, Neil Pearson and Bryn Bowen The Planetary Science Journal, Volume 3, Number 9 LINK (OPEN ACCESS)PDF (OPEN ACCESS) &#8220;We conducted photometric and spectroscopic characterization of near-Earth&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77,7,130,63],"tags":[6381,1854,6382,4852,364,4827,1807,2542,260,197],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31326"}],"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=31326"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31326\/revisions"}],"predecessor-version":[{"id":31327,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31326\/revisions\/31327"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=31326"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=31326"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=31326"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}