Loading…
Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu
Over a broad size range, the shapes of impact fragments from catastrophic disruptions are distributed around the mean axial ratio 2: √2: 1, irrespective of experimental conditions and target materials. Although most blocks on asteroids are likely to be impact fragments, there is not enough quantitat...
Saved in:
Published in: | Icarus (New York, N.Y. 1962) N.Y. 1962), 2022-07, Vol.381, p.115007, Article 115007 |
---|---|
Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
cited_by | cdi_FETCH-LOGICAL-a512t-542ab198343b162bf4c6128f847cb6b0a8ad4a0c0bd4cf9943636f43ca513d453 |
---|---|
cites | cdi_FETCH-LOGICAL-a512t-542ab198343b162bf4c6128f847cb6b0a8ad4a0c0bd4cf9943636f43ca513d453 |
container_end_page | |
container_issue | |
container_start_page | 115007 |
container_title | Icarus (New York, N.Y. 1962) |
container_volume | 381 |
creator | Michikami, Tatsuhiro Hagermann, Axel Morota, Tomokatsu Yokota, Yasuhiro Urakawa, Seitaro Okamura, Hiroyuki Tanabe, Naoya Yumoto, Koki Ebihara, Tatsuki Cho, Yuichiro Ernst, Carolyn M. Hayakawa, Masahiko Hirabayashi, Masatoshi Hirata, Naru Honda, Chikatoshi Honda, Rie Kameda, Shingo Kanamaru, Masanori Kikuchi, Hiroshi Kikuchi, Shota Kouyama, Toru Matsuoka, Moe Miyamoto, Hideaki Noguchi, Takaaki Noguchi, Rina Ogawa, Kazunori Okada, Tatsuaki Sakatani, Naoya Sasaki, Sho Sawada, Hirotaka Sugimoto, Chiho Suzuki, Hidehiko Tanaka, Satoshi Tatsumi, Eri Tsuchiyama, Akira Tsuda, Yuichi Watanabe, Sei-ichiro Yamada, Manabu Yoshikawa, Makoto Yoshioka, Kazuo Sugita, Seiji |
description | Over a broad size range, the shapes of impact fragments from catastrophic disruptions are distributed around the mean axial ratio 2: √2: 1, irrespective of experimental conditions and target materials. Although most blocks on asteroids are likely to be impact fragments, there is not enough quantitative data for reliable statistics on their three-axial lengths and/or ratios because it is difficult to precisely estimate the heights of the blocks. In this study, we evaluate the heights of blocks on asteroid Ryugu by measuring their shadows. The three-axial ratios of ~4100 small blocks with diameters from 5.0 cm to 7.6 m in Ryugu's equatorial region are investigated using eight close-up images of narrower localities taken at altitudes below 500 m, i.e. at |
doi_str_mv | 10.1016/j.icarus.2022.115007 |
format | article |
fullrecord | <record><control><sourceid>hal_swepu</sourceid><recordid>TN_cdi_swepub_primary_oai_DiVA_org_ltu_90045</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><els_id>S0019103522001233</els_id><sourcerecordid>oai_HAL_hal_03674912v1</sourcerecordid><originalsourceid>FETCH-LOGICAL-a512t-542ab198343b162bf4c6128f847cb6b0a8ad4a0c0bd4cf9943636f43ca513d453</originalsourceid><addsrcrecordid>eNp9kUtrGzEUhUVpoG7af9CFtoWMc_WY8cymYNImKRgKJelWXEl3YhnZMtJM0vz7jDOl0E1X9_WdA5fD2CcBSwGiudwtg8M8lqUEKZdC1ACrN2whoINKNlq9ZQsA0VUCVP2OvS9lBwB126kFi3fbTFTh74CRly0eiftQhhzsOIR0KDz1_EjWRioX3KXXhuPBc5vG6CkXXvYYI2U-bPHAkff0xPc0nC5pmsvUpeD5z-fxYfzAznqMhT7-qefs_vrb3dVttflx8_1qvamwFnKoai3Riq5VWlnRSNtr1wjZ9q1eOdtYwBa9RnBgvXZ912nVqKbXyk1y5XWtztnF7Fue6Dhac8xhj_nZJAzma_i1Nik_mDiMpgN4xT_P-BbjP-ztemNOO1DNSndCPoqJ1TPrciolU_9XIMCcwjA7M4dhTmGYOYxJ9mWW0fT2Y6Bsigt0cORDJjcYn8L_DV4AcneVLg</addsrcrecordid><sourcetype>Open Access Repository</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype></control><display><type>article</type><title>Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu</title><source>Elsevier:Jisc Collections:Elsevier Read and Publish Agreement 2022-2024:Freedom Collection (Reading list)</source><creator>Michikami, Tatsuhiro ; Hagermann, Axel ; Morota, Tomokatsu ; Yokota, Yasuhiro ; Urakawa, Seitaro ; Okamura, Hiroyuki ; Tanabe, Naoya ; Yumoto, Koki ; Ebihara, Tatsuki ; Cho, Yuichiro ; Ernst, Carolyn M. ; Hayakawa, Masahiko ; Hirabayashi, Masatoshi ; Hirata, Naru ; Honda, Chikatoshi ; Honda, Rie ; Kameda, Shingo ; Kanamaru, Masanori ; Kikuchi, Hiroshi ; Kikuchi, Shota ; Kouyama, Toru ; Matsuoka, Moe ; Miyamoto, Hideaki ; Noguchi, Takaaki ; Noguchi, Rina ; Ogawa, Kazunori ; Okada, Tatsuaki ; Sakatani, Naoya ; Sasaki, Sho ; Sawada, Hirotaka ; Sugimoto, Chiho ; Suzuki, Hidehiko ; Tanaka, Satoshi ; Tatsumi, Eri ; Tsuchiyama, Akira ; Tsuda, Yuichi ; Watanabe, Sei-ichiro ; Yamada, Manabu ; Yoshikawa, Makoto ; Yoshioka, Kazuo ; Sugita, Seiji</creator><creatorcontrib>Michikami, Tatsuhiro ; Hagermann, Axel ; Morota, Tomokatsu ; Yokota, Yasuhiro ; Urakawa, Seitaro ; Okamura, Hiroyuki ; Tanabe, Naoya ; Yumoto, Koki ; Ebihara, Tatsuki ; Cho, Yuichiro ; Ernst, Carolyn M. ; Hayakawa, Masahiko ; Hirabayashi, Masatoshi ; Hirata, Naru ; Honda, Chikatoshi ; Honda, Rie ; Kameda, Shingo ; Kanamaru, Masanori ; Kikuchi, Hiroshi ; Kikuchi, Shota ; Kouyama, Toru ; Matsuoka, Moe ; Miyamoto, Hideaki ; Noguchi, Takaaki ; Noguchi, Rina ; Ogawa, Kazunori ; Okada, Tatsuaki ; Sakatani, Naoya ; Sasaki, Sho ; Sawada, Hirotaka ; Sugimoto, Chiho ; Suzuki, Hidehiko ; Tanaka, Satoshi ; Tatsumi, Eri ; Tsuchiyama, Akira ; Tsuda, Yuichi ; Watanabe, Sei-ichiro ; Yamada, Manabu ; Yoshikawa, Makoto ; Yoshioka, Kazuo ; Sugita, Seiji</creatorcontrib><description>Over a broad size range, the shapes of impact fragments from catastrophic disruptions are distributed around the mean axial ratio 2: √2: 1, irrespective of experimental conditions and target materials. Although most blocks on asteroids are likely to be impact fragments, there is not enough quantitative data for reliable statistics on their three-axial lengths and/or ratios because it is difficult to precisely estimate the heights of the blocks. In this study, we evaluate the heights of blocks on asteroid Ryugu by measuring their shadows. The three-axial ratios of ~4100 small blocks with diameters from 5.0 cm to 7.6 m in Ryugu's equatorial region are investigated using eight close-up images of narrower localities taken at altitudes below 500 m, i.e. at <5.4 cm/pixel resolution, obtained immediately before the second touch-down of the Hayabusa2 spacecraft. The purpose of this study is to investigate the block shape distribution, which is important for understanding the geological history of asteroid Ryugu. Specifically, the shape distribution is compared to laboratory impact fragments. Our observations indicate that the shape distributions of blocks smaller than 1 m on Ryugu are consistent with laboratory impact fragment shape distributions, implying that the dominant shape-determining process for blocks on Ryugu was impact fragmentation. Blocks several meters in size in the equatorial region seem to be slightly flatter than the rest, suggesting that some blocks are partly buried in a bed of regolith. In conclusion, the shape distributions of blocks from several-cm to several-m in the equatorial region of asteroid Ryugu suggest that these are mainly fragments originating from the catastrophic disruption of their parent body and/or from a later impact.
•Blocks <1 m on Ryugu have similar three-axial shape distributions to laboratory impact fragments.•Blocks several meters in size appear to be slightly flatter.•Some blocks several meters in size are partly buried in a bed of regolith.•The dominant shape-determining process for blocks may be impact fragmentation.</description><identifier>ISSN: 0019-1035</identifier><identifier>ISSN: 1090-2643</identifier><identifier>EISSN: 1090-2643</identifier><identifier>DOI: 10.1016/j.icarus.2022.115007</identifier><language>eng</language><publisher>Elsevier Inc</publisher><subject>Asteroid Ryugu ; Asteroids ; Atmosfärsvetenskap ; Atmospheric science ; Impact process ; Regolith ; Sciences of the Universe ; Surfaces</subject><ispartof>Icarus (New York, N.Y. 1962), 2022-07, Vol.381, p.115007, Article 115007</ispartof><rights>2022 The Authors</rights><rights>Attribution - NonCommercial - NoDerivatives</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-a512t-542ab198343b162bf4c6128f847cb6b0a8ad4a0c0bd4cf9943636f43ca513d453</citedby><cites>FETCH-LOGICAL-a512t-542ab198343b162bf4c6128f847cb6b0a8ad4a0c0bd4cf9943636f43ca513d453</cites><orcidid>0000-0001-9084-2858 ; 0000-0002-1821-5689 ; 0000-0001-5451-9367 ; 0000-0001-6076-3614</orcidid></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><link.rule.ids>230,314,777,781,882,27906,27907</link.rule.ids><backlink>$$Uhttps://u-paris.hal.science/hal-03674912$$DView record in HAL$$Hfree_for_read</backlink><backlink>$$Uhttps://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-90045$$DView record from Swedish Publication Index$$Hfree_for_read</backlink></links><search><creatorcontrib>Michikami, Tatsuhiro</creatorcontrib><creatorcontrib>Hagermann, Axel</creatorcontrib><creatorcontrib>Morota, Tomokatsu</creatorcontrib><creatorcontrib>Yokota, Yasuhiro</creatorcontrib><creatorcontrib>Urakawa, Seitaro</creatorcontrib><creatorcontrib>Okamura, Hiroyuki</creatorcontrib><creatorcontrib>Tanabe, Naoya</creatorcontrib><creatorcontrib>Yumoto, Koki</creatorcontrib><creatorcontrib>Ebihara, Tatsuki</creatorcontrib><creatorcontrib>Cho, Yuichiro</creatorcontrib><creatorcontrib>Ernst, Carolyn M.</creatorcontrib><creatorcontrib>Hayakawa, Masahiko</creatorcontrib><creatorcontrib>Hirabayashi, Masatoshi</creatorcontrib><creatorcontrib>Hirata, Naru</creatorcontrib><creatorcontrib>Honda, Chikatoshi</creatorcontrib><creatorcontrib>Honda, Rie</creatorcontrib><creatorcontrib>Kameda, Shingo</creatorcontrib><creatorcontrib>Kanamaru, Masanori</creatorcontrib><creatorcontrib>Kikuchi, Hiroshi</creatorcontrib><creatorcontrib>Kikuchi, Shota</creatorcontrib><creatorcontrib>Kouyama, Toru</creatorcontrib><creatorcontrib>Matsuoka, Moe</creatorcontrib><creatorcontrib>Miyamoto, Hideaki</creatorcontrib><creatorcontrib>Noguchi, Takaaki</creatorcontrib><creatorcontrib>Noguchi, Rina</creatorcontrib><creatorcontrib>Ogawa, Kazunori</creatorcontrib><creatorcontrib>Okada, Tatsuaki</creatorcontrib><creatorcontrib>Sakatani, Naoya</creatorcontrib><creatorcontrib>Sasaki, Sho</creatorcontrib><creatorcontrib>Sawada, Hirotaka</creatorcontrib><creatorcontrib>Sugimoto, Chiho</creatorcontrib><creatorcontrib>Suzuki, Hidehiko</creatorcontrib><creatorcontrib>Tanaka, Satoshi</creatorcontrib><creatorcontrib>Tatsumi, Eri</creatorcontrib><creatorcontrib>Tsuchiyama, Akira</creatorcontrib><creatorcontrib>Tsuda, Yuichi</creatorcontrib><creatorcontrib>Watanabe, Sei-ichiro</creatorcontrib><creatorcontrib>Yamada, Manabu</creatorcontrib><creatorcontrib>Yoshikawa, Makoto</creatorcontrib><creatorcontrib>Yoshioka, Kazuo</creatorcontrib><creatorcontrib>Sugita, Seiji</creatorcontrib><title>Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu</title><title>Icarus (New York, N.Y. 1962)</title><description>Over a broad size range, the shapes of impact fragments from catastrophic disruptions are distributed around the mean axial ratio 2: √2: 1, irrespective of experimental conditions and target materials. Although most blocks on asteroids are likely to be impact fragments, there is not enough quantitative data for reliable statistics on their three-axial lengths and/or ratios because it is difficult to precisely estimate the heights of the blocks. In this study, we evaluate the heights of blocks on asteroid Ryugu by measuring their shadows. The three-axial ratios of ~4100 small blocks with diameters from 5.0 cm to 7.6 m in Ryugu's equatorial region are investigated using eight close-up images of narrower localities taken at altitudes below 500 m, i.e. at <5.4 cm/pixel resolution, obtained immediately before the second touch-down of the Hayabusa2 spacecraft. The purpose of this study is to investigate the block shape distribution, which is important for understanding the geological history of asteroid Ryugu. Specifically, the shape distribution is compared to laboratory impact fragments. Our observations indicate that the shape distributions of blocks smaller than 1 m on Ryugu are consistent with laboratory impact fragment shape distributions, implying that the dominant shape-determining process for blocks on Ryugu was impact fragmentation. Blocks several meters in size in the equatorial region seem to be slightly flatter than the rest, suggesting that some blocks are partly buried in a bed of regolith. In conclusion, the shape distributions of blocks from several-cm to several-m in the equatorial region of asteroid Ryugu suggest that these are mainly fragments originating from the catastrophic disruption of their parent body and/or from a later impact.
•Blocks <1 m on Ryugu have similar three-axial shape distributions to laboratory impact fragments.•Blocks several meters in size appear to be slightly flatter.•Some blocks several meters in size are partly buried in a bed of regolith.•The dominant shape-determining process for blocks may be impact fragmentation.</description><subject>Asteroid Ryugu</subject><subject>Asteroids</subject><subject>Atmosfärsvetenskap</subject><subject>Atmospheric science</subject><subject>Impact process</subject><subject>Regolith</subject><subject>Sciences of the Universe</subject><subject>Surfaces</subject><issn>0019-1035</issn><issn>1090-2643</issn><issn>1090-2643</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2022</creationdate><recordtype>article</recordtype><recordid>eNp9kUtrGzEUhUVpoG7af9CFtoWMc_WY8cymYNImKRgKJelWXEl3YhnZMtJM0vz7jDOl0E1X9_WdA5fD2CcBSwGiudwtg8M8lqUEKZdC1ACrN2whoINKNlq9ZQsA0VUCVP2OvS9lBwB126kFi3fbTFTh74CRly0eiftQhhzsOIR0KDz1_EjWRioX3KXXhuPBc5vG6CkXXvYYI2U-bPHAkff0xPc0nC5pmsvUpeD5z-fxYfzAznqMhT7-qefs_vrb3dVttflx8_1qvamwFnKoai3Riq5VWlnRSNtr1wjZ9q1eOdtYwBa9RnBgvXZ912nVqKbXyk1y5XWtztnF7Fue6Dhac8xhj_nZJAzma_i1Nik_mDiMpgN4xT_P-BbjP-ztemNOO1DNSndCPoqJ1TPrciolU_9XIMCcwjA7M4dhTmGYOYxJ9mWW0fT2Y6Bsigt0cORDJjcYn8L_DV4AcneVLg</recordid><startdate>20220715</startdate><enddate>20220715</enddate><creator>Michikami, Tatsuhiro</creator><creator>Hagermann, Axel</creator><creator>Morota, Tomokatsu</creator><creator>Yokota, Yasuhiro</creator><creator>Urakawa, Seitaro</creator><creator>Okamura, Hiroyuki</creator><creator>Tanabe, Naoya</creator><creator>Yumoto, Koki</creator><creator>Ebihara, Tatsuki</creator><creator>Cho, Yuichiro</creator><creator>Ernst, Carolyn M.</creator><creator>Hayakawa, Masahiko</creator><creator>Hirabayashi, Masatoshi</creator><creator>Hirata, Naru</creator><creator>Honda, Chikatoshi</creator><creator>Honda, Rie</creator><creator>Kameda, Shingo</creator><creator>Kanamaru, Masanori</creator><creator>Kikuchi, Hiroshi</creator><creator>Kikuchi, Shota</creator><creator>Kouyama, Toru</creator><creator>Matsuoka, Moe</creator><creator>Miyamoto, Hideaki</creator><creator>Noguchi, Takaaki</creator><creator>Noguchi, Rina</creator><creator>Ogawa, Kazunori</creator><creator>Okada, Tatsuaki</creator><creator>Sakatani, Naoya</creator><creator>Sasaki, Sho</creator><creator>Sawada, Hirotaka</creator><creator>Sugimoto, Chiho</creator><creator>Suzuki, Hidehiko</creator><creator>Tanaka, Satoshi</creator><creator>Tatsumi, Eri</creator><creator>Tsuchiyama, Akira</creator><creator>Tsuda, Yuichi</creator><creator>Watanabe, Sei-ichiro</creator><creator>Yamada, Manabu</creator><creator>Yoshikawa, Makoto</creator><creator>Yoshioka, Kazuo</creator><creator>Sugita, Seiji</creator><general>Elsevier Inc</general><general>Elsevier</general><scope>6I.</scope><scope>AAFTH</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>1XC</scope><scope>VOOES</scope><scope>ADTPV</scope><scope>AOWAS</scope><scope>D8T</scope><scope>ZZAVC</scope><orcidid>https://orcid.org/0000-0001-9084-2858</orcidid><orcidid>https://orcid.org/0000-0002-1821-5689</orcidid><orcidid>https://orcid.org/0000-0001-5451-9367</orcidid><orcidid>https://orcid.org/0000-0001-6076-3614</orcidid></search><sort><creationdate>20220715</creationdate><title>Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu</title><author>Michikami, Tatsuhiro ; Hagermann, Axel ; Morota, Tomokatsu ; Yokota, Yasuhiro ; Urakawa, Seitaro ; Okamura, Hiroyuki ; Tanabe, Naoya ; Yumoto, Koki ; Ebihara, Tatsuki ; Cho, Yuichiro ; Ernst, Carolyn M. ; Hayakawa, Masahiko ; Hirabayashi, Masatoshi ; Hirata, Naru ; Honda, Chikatoshi ; Honda, Rie ; Kameda, Shingo ; Kanamaru, Masanori ; Kikuchi, Hiroshi ; Kikuchi, Shota ; Kouyama, Toru ; Matsuoka, Moe ; Miyamoto, Hideaki ; Noguchi, Takaaki ; Noguchi, Rina ; Ogawa, Kazunori ; Okada, Tatsuaki ; Sakatani, Naoya ; Sasaki, Sho ; Sawada, Hirotaka ; Sugimoto, Chiho ; Suzuki, Hidehiko ; Tanaka, Satoshi ; Tatsumi, Eri ; Tsuchiyama, Akira ; Tsuda, Yuichi ; Watanabe, Sei-ichiro ; Yamada, Manabu ; Yoshikawa, Makoto ; Yoshioka, Kazuo ; Sugita, Seiji</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-a512t-542ab198343b162bf4c6128f847cb6b0a8ad4a0c0bd4cf9943636f43ca513d453</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2022</creationdate><topic>Asteroid Ryugu</topic><topic>Asteroids</topic><topic>Atmosfärsvetenskap</topic><topic>Atmospheric science</topic><topic>Impact process</topic><topic>Regolith</topic><topic>Sciences of the Universe</topic><topic>Surfaces</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Michikami, Tatsuhiro</creatorcontrib><creatorcontrib>Hagermann, Axel</creatorcontrib><creatorcontrib>Morota, Tomokatsu</creatorcontrib><creatorcontrib>Yokota, Yasuhiro</creatorcontrib><creatorcontrib>Urakawa, Seitaro</creatorcontrib><creatorcontrib>Okamura, Hiroyuki</creatorcontrib><creatorcontrib>Tanabe, Naoya</creatorcontrib><creatorcontrib>Yumoto, Koki</creatorcontrib><creatorcontrib>Ebihara, Tatsuki</creatorcontrib><creatorcontrib>Cho, Yuichiro</creatorcontrib><creatorcontrib>Ernst, Carolyn M.</creatorcontrib><creatorcontrib>Hayakawa, Masahiko</creatorcontrib><creatorcontrib>Hirabayashi, Masatoshi</creatorcontrib><creatorcontrib>Hirata, Naru</creatorcontrib><creatorcontrib>Honda, Chikatoshi</creatorcontrib><creatorcontrib>Honda, Rie</creatorcontrib><creatorcontrib>Kameda, Shingo</creatorcontrib><creatorcontrib>Kanamaru, Masanori</creatorcontrib><creatorcontrib>Kikuchi, Hiroshi</creatorcontrib><creatorcontrib>Kikuchi, Shota</creatorcontrib><creatorcontrib>Kouyama, Toru</creatorcontrib><creatorcontrib>Matsuoka, Moe</creatorcontrib><creatorcontrib>Miyamoto, Hideaki</creatorcontrib><creatorcontrib>Noguchi, Takaaki</creatorcontrib><creatorcontrib>Noguchi, Rina</creatorcontrib><creatorcontrib>Ogawa, Kazunori</creatorcontrib><creatorcontrib>Okada, Tatsuaki</creatorcontrib><creatorcontrib>Sakatani, Naoya</creatorcontrib><creatorcontrib>Sasaki, Sho</creatorcontrib><creatorcontrib>Sawada, Hirotaka</creatorcontrib><creatorcontrib>Sugimoto, Chiho</creatorcontrib><creatorcontrib>Suzuki, Hidehiko</creatorcontrib><creatorcontrib>Tanaka, Satoshi</creatorcontrib><creatorcontrib>Tatsumi, Eri</creatorcontrib><creatorcontrib>Tsuchiyama, Akira</creatorcontrib><creatorcontrib>Tsuda, Yuichi</creatorcontrib><creatorcontrib>Watanabe, Sei-ichiro</creatorcontrib><creatorcontrib>Yamada, Manabu</creatorcontrib><creatorcontrib>Yoshikawa, Makoto</creatorcontrib><creatorcontrib>Yoshioka, Kazuo</creatorcontrib><creatorcontrib>Sugita, Seiji</creatorcontrib><collection>ScienceDirect Open Access Titles</collection><collection>Elsevier:ScienceDirect:Open Access</collection><collection>CrossRef</collection><collection>Hyper Article en Ligne (HAL)</collection><collection>Hyper Article en Ligne (HAL) (Open Access)</collection><collection>SwePub</collection><collection>SwePub Articles</collection><collection>SWEPUB Freely available online</collection><collection>SwePub Articles full text</collection><jtitle>Icarus (New York, N.Y. 1962)</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Michikami, Tatsuhiro</au><au>Hagermann, Axel</au><au>Morota, Tomokatsu</au><au>Yokota, Yasuhiro</au><au>Urakawa, Seitaro</au><au>Okamura, Hiroyuki</au><au>Tanabe, Naoya</au><au>Yumoto, Koki</au><au>Ebihara, Tatsuki</au><au>Cho, Yuichiro</au><au>Ernst, Carolyn M.</au><au>Hayakawa, Masahiko</au><au>Hirabayashi, Masatoshi</au><au>Hirata, Naru</au><au>Honda, Chikatoshi</au><au>Honda, Rie</au><au>Kameda, Shingo</au><au>Kanamaru, Masanori</au><au>Kikuchi, Hiroshi</au><au>Kikuchi, Shota</au><au>Kouyama, Toru</au><au>Matsuoka, Moe</au><au>Miyamoto, Hideaki</au><au>Noguchi, Takaaki</au><au>Noguchi, Rina</au><au>Ogawa, Kazunori</au><au>Okada, Tatsuaki</au><au>Sakatani, Naoya</au><au>Sasaki, Sho</au><au>Sawada, Hirotaka</au><au>Sugimoto, Chiho</au><au>Suzuki, Hidehiko</au><au>Tanaka, Satoshi</au><au>Tatsumi, Eri</au><au>Tsuchiyama, Akira</au><au>Tsuda, Yuichi</au><au>Watanabe, Sei-ichiro</au><au>Yamada, Manabu</au><au>Yoshikawa, Makoto</au><au>Yoshioka, Kazuo</au><au>Sugita, Seiji</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu</atitle><jtitle>Icarus (New York, N.Y. 1962)</jtitle><date>2022-07-15</date><risdate>2022</risdate><volume>381</volume><spage>115007</spage><pages>115007-</pages><artnum>115007</artnum><issn>0019-1035</issn><issn>1090-2643</issn><eissn>1090-2643</eissn><abstract>Over a broad size range, the shapes of impact fragments from catastrophic disruptions are distributed around the mean axial ratio 2: √2: 1, irrespective of experimental conditions and target materials. Although most blocks on asteroids are likely to be impact fragments, there is not enough quantitative data for reliable statistics on their three-axial lengths and/or ratios because it is difficult to precisely estimate the heights of the blocks. In this study, we evaluate the heights of blocks on asteroid Ryugu by measuring their shadows. The three-axial ratios of ~4100 small blocks with diameters from 5.0 cm to 7.6 m in Ryugu's equatorial region are investigated using eight close-up images of narrower localities taken at altitudes below 500 m, i.e. at <5.4 cm/pixel resolution, obtained immediately before the second touch-down of the Hayabusa2 spacecraft. The purpose of this study is to investigate the block shape distribution, which is important for understanding the geological history of asteroid Ryugu. Specifically, the shape distribution is compared to laboratory impact fragments. Our observations indicate that the shape distributions of blocks smaller than 1 m on Ryugu are consistent with laboratory impact fragment shape distributions, implying that the dominant shape-determining process for blocks on Ryugu was impact fragmentation. Blocks several meters in size in the equatorial region seem to be slightly flatter than the rest, suggesting that some blocks are partly buried in a bed of regolith. In conclusion, the shape distributions of blocks from several-cm to several-m in the equatorial region of asteroid Ryugu suggest that these are mainly fragments originating from the catastrophic disruption of their parent body and/or from a later impact.
•Blocks <1 m on Ryugu have similar three-axial shape distributions to laboratory impact fragments.•Blocks several meters in size appear to be slightly flatter.•Some blocks several meters in size are partly buried in a bed of regolith.•The dominant shape-determining process for blocks may be impact fragmentation.</abstract><pub>Elsevier Inc</pub><doi>10.1016/j.icarus.2022.115007</doi><orcidid>https://orcid.org/0000-0001-9084-2858</orcidid><orcidid>https://orcid.org/0000-0002-1821-5689</orcidid><orcidid>https://orcid.org/0000-0001-5451-9367</orcidid><orcidid>https://orcid.org/0000-0001-6076-3614</orcidid><oa>free_for_read</oa></addata></record> |
fulltext | fulltext |
identifier | ISSN: 0019-1035 |
ispartof | Icarus (New York, N.Y. 1962), 2022-07, Vol.381, p.115007, Article 115007 |
issn | 0019-1035 1090-2643 1090-2643 |
language | eng |
recordid | cdi_swepub_primary_oai_DiVA_org_ltu_90045 |
source | Elsevier:Jisc Collections:Elsevier Read and Publish Agreement 2022-2024:Freedom Collection (Reading list) |
subjects | Asteroid Ryugu Asteroids Atmosfärsvetenskap Atmospheric science Impact process Regolith Sciences of the Universe Surfaces |
title | Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu |
url | http://sfxeu10.hosted.exlibrisgroup.com/loughborough?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-01-17T07%3A47%3A46IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-hal_swepu&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=Three-axial%20shape%20distributions%20of%20pebbles,%20cobbles%20and%20boulders%20smaller%20than%20a%20few%20meters%20on%20asteroid%20Ryugu&rft.jtitle=Icarus%20(New%20York,%20N.Y.%201962)&rft.au=Michikami,%20Tatsuhiro&rft.date=2022-07-15&rft.volume=381&rft.spage=115007&rft.pages=115007-&rft.artnum=115007&rft.issn=0019-1035&rft.eissn=1090-2643&rft_id=info:doi/10.1016/j.icarus.2022.115007&rft_dat=%3Chal_swepu%3Eoai_HAL_hal_03674912v1%3C/hal_swepu%3E%3Cgrp_id%3Ecdi_FETCH-LOGICAL-a512t-542ab198343b162bf4c6128f847cb6b0a8ad4a0c0bd4cf9943636f43ca513d453%3C/grp_id%3E%3Coa%3E%3C/oa%3E%3Curl%3E%3C/url%3E&rft_id=info:oai/&rft_id=info:pmid/&rfr_iscdi=true |