[{"@context":"http:\/\/schema.org\/","@type":"BlogPosting","@id":"https:\/\/wiki.edu.vn\/en\/wiki19\/52768-1998-or2-wikipedia\/#BlogPosting","mainEntityOfPage":"https:\/\/wiki.edu.vn\/en\/wiki19\/52768-1998-or2-wikipedia\/","headline":"(52768) 1998 OR2 – Wikipedia","name":"(52768) 1998 OR2 – Wikipedia","description":"From Wikipedia, the free encyclopedia This article needs to be updated. The reason given is: New Arecibo radar results presented","datePublished":"2022-11-05","dateModified":"2022-11-05","author":{"@type":"Person","@id":"https:\/\/wiki.edu.vn\/en\/wiki19\/author\/lordneo\/#Person","name":"lordneo","url":"https:\/\/wiki.edu.vn\/en\/wiki19\/author\/lordneo\/","image":{"@type":"ImageObject","@id":"https:\/\/secure.gravatar.com\/avatar\/c9645c498c9701c88b89b8537773dd7c?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/c9645c498c9701c88b89b8537773dd7c?s=96&d=mm&r=g","height":96,"width":96}},"publisher":{"@type":"Organization","name":"Enzyklop\u00e4die","logo":{"@type":"ImageObject","@id":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","url":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","width":600,"height":60}},"image":{"@type":"ImageObject","@id":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/b\/bd\/Ambox_current_red_Asia_Australia.svg\/42px-Ambox_current_red_Asia_Australia.svg.png","url":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/b\/bd\/Ambox_current_red_Asia_Australia.svg\/42px-Ambox_current_red_Asia_Australia.svg.png","height":"34","width":"42"},"url":"https:\/\/wiki.edu.vn\/en\/wiki19\/52768-1998-or2-wikipedia\/","wordCount":4575,"articleBody":"From Wikipedia, the free encyclopediaThis article needs to be updated. The reason given is: New Arecibo radar results presented at the 8th IAA Planetary Defense Conference in April 2023[3]. Please help update this article to reflect recent events or newly available information.  (April 2023)(52768) 1998 OR2 (provisional designation 1998 OR2) is an asteroid on an eccentric orbit, classified as a near-Earth object and potentially hazardous asteroid of the Amor group, with a diameter of 2 kilometers (1.2\u00a0mi). It was discovered on 24 July 1998, by astronomers of the Near-Earth Asteroid Tracking (NEAT) program at the Haleakala Observatory, Hawaii.[2] It is one of the brightest and therefore largest potentially hazardous asteroids known to exist.[7] With an observation arc of 32 years, the asteroid has a well-determined orbit, and its trajectory is well known through the year 2197.[1] The asteroid’s orbit is only potentially hazardous on a time scale of thousands of years.[8]Table of ContentsOrbit and classification[edit]Close approaches[edit]Physical characteristics[edit]Rotation period[edit]Diameter and albedo[edit]References[edit]External links[edit]Orbit and classification[edit]Time lapse of asteroid 1998 OR2‘s motion in the sky on 9 April 2020Orbit diagram of 1998 OR2Arecibo radar images of 1998 OR2 taken over a two-hour period in April 2020Animation of 1998 OR2 close approach in 20201998 OR2 is a member of the dynamical Amor group of near-Earth asteroids,[1][2] and therefore does not currently cross Earth’s orbit. The asteroid’s closest approach to the Sun is just outside Earth’s farthest distance from the Sun. When the asteroid has a perihelion point less than 1.017 AU (Earth’s aphelion), it is classified an Apollo asteroid. This asteroid’s category flips back and forth as time passes, due to minor perturbations of its orbit.It orbits the Sun at a distance of 1.0\u20133.7\u00a0AU once every 3 years and 8 months (1,344 days; semi-major axis of 2.38\u00a0AU). Its orbit has a high eccentricity of 0.57 and an inclination of 6\u00b0 with respect to the ecliptic. With its sufficiently large aphelion, this asteroid is also classified as a Mars-crosser, crossing the orbit of Mars at 1.66\u00a0AU.[1]The body’s observation arc begins with a precovery published by the Digitized Sky Survey taken at the Siding Spring Observatory in June 1986, more than 12 years prior to its official discovery observation at Haleakala Observatory, Hawaii.[2]Close approaches[edit]With an absolute magnitude of approximately 15.8,[2]1998 OR2 is one of the brightest and presumably largest-known potentially hazardous asteroids (see PHA-list).[7] It currently has an Earth minimum orbital intersection distance of 0.0154\u00a0AU (2,300,000\u00a0km), which translates into 6.0 lunar distances (LD).[1] On 16 April 2079, this asteroid will make a near-Earth encounter at a safe distance of 0.0118\u00a0AU (4.59\u00a0LD), and pass the Moon at 0.0092\u00a0AU (3.6\u00a0LD).[1] The asteroid’s orbit is only potentially hazardous on a time scale of hundreds, if not thousands, of years.On 29 April 2020 at 09:56 UTC, the asteroid passed at a distance of 0.042\u00a0AU (6.3\u00a0million\u00a0km; 16\u00a0LD) from Earth.[1] With observations as recent as April 2020 and a 32-year observation arc, the 2020 close approach distance was known with an accuracy of roughly \u00b16\u00a0km.[9] (For comparison, Venus will be 0.29\u00a0AU or 43\u00a0million\u00a0km or 110\u00a0LD from Earth on 3 June 2020.)History of close approaches of large near-Earth objects since 1908\u2009(A)Physical characteristics[edit]  Animation of radar images showing 1998 OR2‘s rotationAccording to observations by the NASA IRTF telescope during the ExploreNEOs Warm Spitzer program, 1998 OR2 is a rather rare L-type asteroid.[10] Delay-Doppler radar observations by the Arecibo Observatory in April 2020 have shown that 1998 OR2 bears a large, crater-like concavity in its shape.[11] These radar observations have also resolved several other topographic features on the asteroid’s surface, such as hills and ridges.[12]Rotation period[edit]In 2009, rotational lightcurves of 1998 OR2 were obtained from photometric observations by astronomers in Salvador, Brazil, and during the Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS). Lightcurve analysis gave a rotation period of 3.198 and 4.112 hours with a brightness amplitude of 0.29 and 0.16 magnitude, respectively (U=2\/2+).[13][14] The latter rotation period of 4.1 hours was later confirmed by radar observations of the asteroid in 2020.[12][11]Diameter and albedo[edit]The Collaborative Asteroid Lightcurve Link (CALL) assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 2.15\u00a0km (1.34\u00a0mi) based on an absolute magnitude of 15.7.[15] It is the first near-earth asteroid to show evidence of shock darkening: the slow darkening of the surface over time, from micrometeorites and solar wind.[5]As of 2020, this minor planet has not been named.[2]References[edit]^ a b c d e f g h i j “Small-Body Database Lookup: 52768 (1998 OR2)” (2022-12-26 last obs.). Jet Propulsion Laboratory. Retrieved 5 April 2023.^ a b c d e f g h “52768 (1998 OR2)”. Minor Planet Center. Retrieved 7 March 2020.^ a b c Devog\u00e8le, Maxime;  et\u00a0al. (5 April 2023). (52768) 1998 OR2, an analog to (16) Psyche in the near-Earth space?. 8th IAA Planetary Defense Conference. Vienna, Austria. p.\u00a09. Archived from the original on 5 April 2023.^ “Coordinate transformations”. Astronomy and Astrophysics. European Southern Observatory. January 1998. Archived from the original on 17 June 2021. Retrieved 5 April 2023.^ a b c Battle, Adam; Reddy, Vishnu; Sanchez, Juan A.; Sharkey, Benjamin; Pearson, Neil; Bowen, Bryn (September 2022). “Physical Characterization of Near-Earth Asteroid (52768) 1998 OR2: Evidence of Shock Darkening\/Impact Melt”. The Planetary Science Journal. 3 (9): 13. arXiv:2210.03049. Bibcode:2022PSJ…..3..226B. doi:10.3847\/PSJ\/ac7223. 226.^ Hus\u00e1rik, Marek; Ivanova, Oleksandra (September 2021). Photometric results of two PHAs: (52768) 1998 OR2 and (99942) Apophis. 16th Europlanet Science Congress 2022. Vol.\u00a016. Granada, Spain: Europlanet Society. Bibcode:2022EPSC…16..671H. doi:10.5194\/epsc2022-671. EPSC2022-671.^ a b “List of the Potentially Hazardous Asteroids (PHAs)”. Minor Planet Center. Retrieved 24 January 2018.^ 1998OR2 MOID over the next 2700 years \u2013 Peter Thomas^ JPL #277 (solution date: 2020-Apr-29) (MaxDist of 0.0420485754979265) \u2013 (MinDist of 0.0420484977243086) * 149597870.7 = 12\u00a0km^ Thomas, Cristina A.; Emery, Joshua P.; Trilling, David E.; Delb\u00f3, Marco; Hora, Joseph L.; Mueller, Michael (January 2014). “Physical characterization of Warm Spitzer-observed near-Earth objects”. Icarus. 228: 217\u2013246. arXiv:1310.2000. Bibcode:2014Icar..228..217T. doi:10.1016\/j.icarus.2013.10.004. S2CID\u00a0119278697.^ a b Virkki, A. K. (23 April 2020). “Arecibo Continues Operations through Pandemic to Observe Potentially Hazardous Asteroid 1998 OR2”. Planetary Radar Science Group. NAIC-Arecibo Observatory. Retrieved 23 April 2020.^ a b Kotala, Zenaida Gonzalez (23 April 2020). “Asteroid Visiting Earth’s Neighborhood Brings its Own Face Mask”. UCF Today. University of Central Florida. Retrieved 23 April 2020.^ Betzler, Alberto Silva; Novaes, Alberto Brum (October 2009). “Photometric Observations of 1998 OR2, 1999 AQ10, and 2008 TC3”. The Minor Planet Bulletin. 36 (4): 145\u2013147. Bibcode:2009MPBu…36..145B. ISSN\u00a01052-8091.^ Koehn, Bruce W.; Bowell, Edward G.; Skiff, Brian A.; Sanborn, Jason J.; McLelland, Kyle P.; Pravec, Petr;  et\u00a0al. (October 2014). “Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) – 2009 January through 2009 June”. The Minor Planet Bulletin. 41 (4): 286\u2013300. Bibcode:2014MPBu…41..286K. ISSN\u00a01052-8091.^ “LCDB Data for (52768)”. Asteroid Lightcurve Database (LCDB). Retrieved 7 March 2020.External links[edit]Wikimedia ErrorOur servers are currently under maintenance or experiencing a technical problem.Please try again in a few\u00a0minutes.See the error message at the bottom of this page for more\u00a0information. 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