25143 Itokawa

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25143 Itokawa
SMASS = S (IV)[3]
Sqw[12]
  • S[13]
  • Q[6]
    • 18.61[14] · 18.95 (R)[15]
    19.00[13] · 19.2[1][3]
    19.48[6][7] · 19.51±0.09[5]

    25143 Itokawa (provisional designation 1998 SF36) is a sub-kilometer

    rotation period of 12.1 hours and measures approximately 330 meters (1,100 feet) in diameter. Due to its low density and high porosity, Itokawa is considered to be a rubble pile
    , consisting of numerous boulders of different sizes rather than of a single solid body.

    It was the first asteroid to be the target of a

    visited by a spacecraft
    prior to the DART mission to Dimorphos in 2022.

    Discovery and naming

    Itokawa was discovered on 26 September 1998 by astronomers with the

    M.P.C. 49281).[17]

    Orbit and classification

    Itokawa belongs to the

    lunar distances.[3]

    Left: orbital diagram of Itokawa on December 2006. Right: animated orbits of Itokawa (green) and Earth (blue) around the Sun.

    Exploration

    This artist's impression, based on detailed spacecraft observations, shows the strange peanut-shaped asteroid Itokawa.

    In 2000, it was selected as the target of Japan's

    Japan Aerospace Exploration Agency reported that dust collected during Hayabusa's voyage was indeed from the asteroid.[18]

    Surface features

    Names of major surface features were proposed by Hayabusa scientists and accepted by the Working Group for Planetary System Nomenclature of the International Astronomical Union.[16] Also, the Hayabusa science team is using working names for smaller surface features.[19][20] The following tables list the names of geological features on the asteroid.[16] No naming conventions have been disclosed for surface features on Itokawa.

    Craters

    Ten impact craters on the surface of Itokawa were named on 18 February 2009.[21]

    Regio Coordinates Diameter (km) Approval Date Named After Ref
    Catalina 17°S 14°E / 17°S 14°E / -17; 14 (Catalina) 0.02 2009 Catalina Station (astronomical observatory) in Arizona, United States WGPSN
    Fuchinobe 34°N 91°W / 34°N 91°W / 34; -91 (Fuchinobe) 0.04 2009 Fuchinobe in
    Sagamihara
    , Japan    		 WGPSN
    Gando 76°S 155°W / 76°S 155°W / -76; -155 (Gando) n.a. 2009 Gando, Canary Islands; Spanish launch facility WGPSN
    Hammaguira 18°S 155°W / 18°S 155°W / -18; -155 (Hammaguira) 0.03 2009 Hammaguir, Algeria; abandoned French launch site and missile testing range in the Sahara desert WGPSN
    Kamisunagawa 28°S 45°E / 28°S 45°E / -28; 45 (Kamisunagawa) 0.01 2009
    Kamisunagawa
    , town in Hokkaido Japan, where a microgravity test facility is located    		 WGPSN
    Kamoi 6°N 116°W / 6°N 116°W / 6; -116 (Kamoi) 0.01 2009 Japanese town of Kamoi in Yokohama, location of the NEC Toshiba Space Systems Ltd. factory WGPSN
    Komaba 10°S 102°E / 10°S 102°E / -10; 102 (Komaba) 0.03 2009 Komaba in
    Meguro
    , Japan, where the Institute of Space and Astronautical Science is located    		 WGPSN
    Laurel 1°N 162°E / 1°N 162°E / 1; 162 (Laurel) 0.02 2009 U.S. city of Laurel in Maryland, where APL/JHU is located WGPSN
    Miyabaru 40°S 116°W / 40°S 116°W / -40; -116 (Miyabaru) 0.09 2009 Radar site of the Uchinoura Space Center in Japan WGPSN
    San Marco 28°S 41°W / 28°S 41°W / -28; -41 (San Marco) n.a. 2009
    San Marco platform
    , an old oil platform near Kenya that served as a launch pad for Italian spacecraft    		 WGPSN

    Regiones

    Regio or regiones are large area marked by reflectivity or color distinctions from adjacent areas in planetary geology. The following regiones have been named on Itokawa.[16][21]

    Regio Coordinates Diameter (km) Approval Date Named After Ref
    Arcoona Regio 28°N 202°E / 28°N 202°E / 28; 202 (Arcoona) 0.16 Feb. 18, 2009 Arcoona, Australia WGPSN
    LINEAR Regio 40°S 232°E / 40°S 232°E / -40; 232 (LINEAR) 0.12 Feb. 18, 2009 Lincoln Near-Earth Asteroid Research WGPSN
    MUSES-C Regio 70°S 60°E / 70°S 60°E / -70; 60 (MUSES-C) 0.3 2006 MUSES-C, name of the
    Hayabusa
    probe prior to launch    		 WGPSN
    Ohsumi Regio 33°N 207°E / 33°N 207°E / 33; 207 (Ohsumi) 0.14 Feb. 18, 2009 Ōsumi Peninsula WGPSN
    Sagamihara Regio 80°N 15°E / 80°N 15°E / 80; 15 (Sagamihara) 0.23 2006 Sagamihara, a town in Japan where Institute of Space and Astronautical Science is located WGPSN
    Uchinoura Regio 40°N 90°E / 40°N 90°E / 40; 90 (Uchinoura) 0.07 2006 Uchinoura, a town in Japan (now part of Kimotsuki), the location of Uchinoura Space Center, Hayabusa launch site WGPSN
    Yoshinobu Regio 39°S 117°E / 39°S 117°E / -39; 117 (Yoshinobu) 0.16 Feb. 18, 2009 Launch site in the Tanegashima Space Center, Japan WGPSN

    Physical characteristics

    densities suggest that these were stand-alone bodies that came into contact later on, making the rubble pile also a likely contact binary.[22]
    Goldstone and Arecibo[23]

    Itokawa is a stony

    Goldstone in 2001 observed an ellipsoid 630±60 meters long and 250±30 meters wide.[23]

    The Hayabusa mission confirmed these findings and also suggested that Itokawa may be a

    Yarkovsky–O'Keefe–Radzievskii–Paddack effect measurements, a small section of Itokawa is estimated to have a density of 2.9 g/cm3, whereas a larger section is estimated to have a density of 1.8 g/cm3.[4][25]

    Rotation period and poles

    Since 2001, a large number of rotational

    Ďurech (12.1323 h),[31] and Nishihara (12.1324 h).[15]

    Composition

    The 26 August 2011 issue of Science devoted six articles to findings based on dust that Hayabusa had collected from Itokawa.[32] Scientists' analysis suggested that Itokawa was probably made up from interior fragments of a larger asteroid that broke apart.[33] Dust collected from the asteroid surface is thought to have been exposed there for about eight million years.[32]

    Scientists used varied techniques of

    meteorites known as "low-total-iron, low metal ordinary chondrites".[34] Another team of scientists determined that the dark iron color on the surface of Itokawa was the result of abrasion by micrometeoroids and high-speed particles from the Sun which had converted the normally whitish iron oxide coloring.[34]

    2018 Hayabusa results

    Two

    inner Solar System and carbonaceous chondrite water isotope levels.[35] Daly et al. report "OH and H2O" apparently formed by implantation of solar wind hydrogen. The rims of an olivine particle "show an enrichment of up to ~1.2 at % in OH and H2O".[36] The water concentrations of the Itokawa grains would indicate an estimated BSI (Bulk Silicate Itokawa) water content in line with Earth's bulk water, and that Itokawa had been a "water-rich asteroid".[37]

    2020 Hayabusa results

    At the 2020 Lunar and Planetary Science Conference, a third group reported water and organics, via a third Hayabusa particle- RA-QD02-0612, or "Amazon." Olivine, pyroxene, and albite contain water. Isotopic compositions indicate a clear extraterrestrial origin.[38]

    2021 Hayabusa results

    A further report by Daly's group was published which supported the theory that a large source of Earth's water has come from hydrogen atoms carried on particles in the solar wind which combine with oxygen on asteroids and then arrive on Earth in space dust. Using atom probe tomography the study found hydroxide and water molecules on the surface of a single grain from particles retrieved from the asteroid Itokawa by the Japanese space probe Hayabusa.[39][40]

    Dust ponds are identified in the asteroid. They are a phenomenon where pockets of dust are seen in Celestial bodies without a significant atmosphere. Smooth deposits of dust accumulate in depressions on the surface of the body (like craters), contrasting from the Rocky terrain around them. [41] In the Sagamihara and Muses-Sea regions of the asteroid dust ponds were identified. Dust particles had a size varying from millimeters to less than a centimeter.

    See also

    Notes

    1. ^ Lightcurve plot of (25143) Itokawa, Palmer Divide Observatory (716) by B. D. Warner (2004). Summary figures at the LCDB.

    References

    1. ^ a b c d e f "25143 Itokawa (1998 SF36)". Minor Planet Center. Retrieved 25 February 2019.
    2. ISBN 978-3-540-34361-5
      .
    3. ^ a b c d e f g "JPL Small-Body Database Browser: 25143 Itokawa (1998 SF36)" (2019-02-04 last obs.). Jet Propulsion Laboratory. Retrieved 25 February 2019.
    4. ^
      S2CID 206508294
      . Retrieved 25 February 2019.
    5. ^
      S2CID 44827674
      .
    6. ^ a b c d e "LCDB Data for (25143) Itokawa". Asteroid Lightcurve Database (LCDB). Retrieved 15 August 2017.
    7. ^
      doi:10.1051/0004-6361:20021437
      .
    8. ^
      S2CID 37768313
      .
    9. ^
      doi:10.1051/0004-6361:20030819
      .
    10. doi:10.1088/0004-6256/142/3/85
      .
    11. ^ S. M. Lederer, et al., "Physical characteristics of Hayabusa target Asteroid 25143 Itokawa", Icarus, v. 173, pp. 153–165 (2005)
    12. S2CID 119278697
      .
    13. ^
      S2CID 119258489
      .
    14. doi:10.1093/pasj/54.4.635
      .
    15. ^
      Bibcode:2005LPI....36.1833N
      .
    16. ^ a b c d "Official Approval of Names on Itokawa by IAU". Press Release of JAXA. 3 March 2009. Retrieved 25 February 2019.
    17. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 15 August 2017.
    18. ^ Atkinson, Nancy (16 November 2010). "Confirmed: Hayabusa Nabbed Asteroid Particles". Universe Today. Archived from the original on 6 December 2010. Retrieved 16 November 2010.
    19. ^ "Itowaka Geological Map". Archived from the original on 26 February 2009. Retrieved 11 August 2008.{{cite news}}: CS1 maint: bot: original URL status unknown (link)
    20. ^ "Local site names on Itowaka". Archived from the original on 26 February 2009. Retrieved 11 August 2008.{{cite news}}: CS1 maint: bot: original URL status unknown (link)
    21. ^ a b "Planetary Names: Itokawa". Gazetteer of Planetary Nomenclature – USGS Astrogeology Research Program. Retrieved 25 February 2019.
    22. ^ "The Anatomy of an Asteroid". ESO Press Release. Retrieved 6 February 2014.
    23. ^
      Bibcode:2001DPS....33.4113O. Archived from the original
      (PDF) on 24 December 2016. Retrieved 25 February 2019.
    24. ^ "Hayabusa: Itokawa Beckons as Japan's Spacecraft Searches for Places to Touch Down". Archived from the original on 12 May 2008. Retrieved 11 August 2008.{{cite news}}: CS1 maint: bot: original URL status unknown (link)
    25. ^ "The Anatomy of an Asteroid". ESO. 5 February 2014. Retrieved 5 February 2014.
    26. Bibcode:2001AAS...199.6303L
      .
    27. Bibcode:2001DPS....33.5909L
      .
    28. doi:10.1016/j.icarus.2005.02.002
      .
    29. S2CID 55758400
      .
    30. ISSN 1052-8091
      .
    31. doi:10.1051/0004-6361:200809663
      .
    32. ^ a b "Asteroid Dust Confirms Meteorite Origins". The New York Times. 25 August 2011. Retrieved 26 August 2011.
    33. ^
      S2CID 10271142
      .
    34. ^ a b "Most Earth meteorites linked to single asteroid". Los Angeles Times. 26 August 2011. Retrieved 26 August 2011.
    35. PMID 31114801
      .
    36. ^ Daly, L; Lee, M; Hallis, L; Bland, P; Reddy, S; et al. (2018). "The origin of hydrogen in space weathered rims of Itokawa regolith particles" (PDF). 2018 Hayabusa Symposium (PDF).
    37. ^ Jin Z; Bose M (2018). "Establishing Itokawa's water contribution to Earth" (PDF). 2018 Hayabusa Symposium (PDF).
    38. ^ Chan, Q; Brunetto, R; Kebukawa, Y; Noguchi, T; Stephant, A; Franchi, I; Zhao, X; Johnson, D; Starkey, N; Anand, M; Russell, S; Schofield, P; Price, M; McDermott, K; Bradley, R; Gilmour, J; Lyon, I; Eithers, P; Lee, M; Sano, Y; Grady, M (2020). First Identification of Indigenous Organic Matter Alongside Water In Itokawa Particle Returned By The Hayabusa Mission. 51st LPSC. Sec. H2O abundance and isotopic composition
    39. S2CID 244744492
      .
    40. ^ Daly, Luke; Lee, Martin R.; Timms, Nick; Bland, Phil (30 November 2021). "Up to half of Earth's water may come from solar wind and space dust". Phys Org.
    41. ^ "Eros's puzzling surface". skyandtelescope.org. Retrieved 18 October 2023.

    Further reading

    • Normile, D (30 April 2010). "Spunky Hayabusa Heads Home With Possible Payload". Science. 328 (5978): 565.
      PMID 20430991
      .

    External links

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