{"id":39973,"date":"2025-12-28T22:58:43","date_gmt":"2025-12-28T21:58:43","guid":{"rendered":"https:\/\/karmaka.de\/?p=39973"},"modified":"2025-12-28T22:58:44","modified_gmt":"2025-12-28T21:58:44","slug":"the-geology-of-a-small-main-belt-s-class-binary-asteroid-system-dinkinesh-and-its-contact-binary-satellite-selam-as-observed-by-the-lucy-mission","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=39973","title":{"rendered":"The Geology of a Small Main-belt S-class Binary Asteroid System: Dinkinesh and Its Contact Binary Satellite Selam as Observed by the Lucy Mission<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>E. B. Bierhaus, S. Marchi, S. J. Robbins, S. Mottola, W. F. Bottke, K. Noll, J. F. Bell III, J. M. Sunshine, J. Spencer, D. Britt<\/p>\n\n\n\n<p>The Planetary Science Journal, Volume 6, Number 12, published: 22 December 2025<\/p>\n\n\n\n<p><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/PSJ\/ae1968\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/PSJ\/ae1968\/pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;The Lucy spacecraft flew past the \u223c738 m diameter, S-class main-belt asteroid (152830) Dinkinesh on 2023 November 1, revealing a satellite named Selam. We used images acquired during the flyby to evaluate surface features on both Dinkinesh and Selam. We find a shallow crater size\u2013frequency distribution (SFD) for Dinkinesh, consistent with crater SFDs observed on other subkilometer asteroids. We derive crater depth-to-diameter ratios near 0.1, also consistent with typical values seen on other asteroids. We calculate a cumulative boulder SFD for Dinkinesh with power-law index 3.93 \u00b1 0.15 slightly steeper though in the range of other S-class asteroids. We find growing evidence that boulder SFDs are, on average, steeper for S-class than C-complex asteroids. Two major surface features on Dinkinesh, Sumak Fossa (a large trough) and Fab Dorsum (an equatorial ridge), are likely an outcome of YORP spinning up Dinkinesh fast enough to produce failure. A self-consistent structure for Dinkinesh that complies with the global shape, feature morphologies, and the estimated 10\u201320 Myr YORP spin-up timescale is a rubble-pile object with a nearly strengthless surface and an interior strength that is less than tens of Pa. Selam could have formed via YORP-driven mass shedding from Dinkinesh, though other formation mechanisms are possible. Combining a low-strength surface with the crater population and an impact model, we estimate a \u223c1 Myr surface age for Dinkinesh. The presence of mass wasting and young troughs indicates that stress accumulation and release continue on Dinkinesh to the present day.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>E. B. Bierhaus, S. Marchi, S. J. Robbins, S. Mottola, W. F. Bottke, K. Noll, J. F. Bell III, J. M. Sunshine, J. Spencer, D. Britt The Planetary Science Journal, Volume 6, Number 12, published:&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77,5659,3035,181],"tags":[6502,6676,1854,5657,1673,270],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39973"}],"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=39973"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39973\/revisions"}],"predecessor-version":[{"id":39974,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/39973\/revisions\/39974"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=39973"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=39973"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=39973"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}