(52768) 1998 OR2

2024-06-10T10:14:27Z

95.231.234.179: Never created damage on earth.

{{Short description|Asteroid}}
{{update|date=April 2023|reason=New Arecibo radar results presented at the 8th IAA Planetary Defense Conference in April 2023<ref name="PDC-Devogele2023"/>}}
{{Use dmy dates|date=September 2020}}
{{DISPLAYTITLE:{{mp|(52768) 1998 OR|2}}}}
{{Infobox planet
| minorplanet = yes
| name = {{mp|(52768) 1998 OR|2}}
| background = #FFC2E0
| image = 1998 OR2 Arecibo.png
| image_scale =
| caption = [[Arecibo Observatory]] radar image of {{mp|1998 OR|2}} with a crater on 18 April 2020
| discovery_ref = <ref name="jpldata" /><ref name="MPC-object" />
| discoverer = [[Near-Earth Asteroid Tracking|NEAT]]
| discovery_site = [[Haleakala Observatory|Haleakala Obs.]]
| discovered = 24 July 1998
| mpc_name = (52768) {{mp|1998 OR|2}}
| alt_names = {{mp|1998 OR|2}}
| pronounced =
| named_after = 
| mp_category = [[Amor asteroid|Amor]]{{·}}[[Near-Earth object|NEO]]{{·}}[[Potentially hazardous object|PHA]]<ref name="jpldata" /><ref name="MPC-object" />
| orbit_ref = <ref name="jpldata" />
| epoch = 25 February 2023 ([[Julian day|JD]] 2460000.5 )
| uncertainty = 0
| observation_arc = 35.49 yr (12,963 days)
| earliest_precovery_date = 30 June 1987 ([[Siding Spring Observatory|Siding Spring Obs.]])
| aphelion = 3.750 [[Astronomical unit|AU]]
| perihelion = 1.011 AU
| semimajor = 2.380 AU
| eccentricity = 0.5754
| period = 3.67 [[Julian year (astronomy)|yr]] (1,342 days)
| mean_anomaly = 280.159[[Degree (angle)|°]]
| mean_motion = {{Deg2DMS|0.2683561|sup=ms}} / day
| inclination = 5.878°
| asc_node = 26.942°
| arg_peri = 174.580°
| moid = {{convert|0.00866|AU|LD|abbr=on}}
| physical_ref = <ref name="PDC-Devogele2023"/>{{rp|page=6}}
| dimensions = {{val|2.08|x|1.93|x|1.60}} km<br/>(± {{val|0.10|x|0.10|x|0.03}} km)
| mean_diameter = {{val|1.78|0.10|u=km}}
| surface_area = {{val|10.67|u=km2}}
| volume = {{val|3.0|0.5|u=km3}}
| mass =
| density = {{val|3.2|0.2|u=g/cm3}}
| rotation = {{val|4.10872|0.00001|u=h}}
| pole_ecliptic_lat = {{val|20.7|5|u=°}}
| pole_ecliptic_lon = {{val|332.3|5|u=°}}
| axial_tilt = {{val|69.3|5|u=°}} (wrt [[ecliptic]]){{efn|name=pole|{{mp|1998 OR|2}}'s rotational north pole direction is given in terms of [[ecliptic coordinates]], where {{mvar|λ}} is [[ecliptic longitude]] and {{mvar|β}} is [[ecliptic latitude]].<ref name="PDC-Devogele2023"/>{{rp|pages=6}} {{mvar|β}} is the angular offset from the [[ecliptic plane]], whereas [[inclination]] {{mvar|i}} with respect to the ecliptic is the angular offset of the asteroid's rotational north pole from the [[ecliptic north pole]] at {{nobr| {{mvar|β}} {{=}} +90° ;}} {{mvar|i}} with respect to the ecliptic would be the [[Angle#Combining angle pairs|complement]] of {{mvar|β}}.<ref name="coordstransform"/> Therefore, given {{nobr| {{mvar|β}} {{=}} +20.7° ,}} {{nobr| {{mvar|i}} {{=}} 90° – (+20.7°) {{=}} 69.3° }} from the ecliptic.}}
| albedo = 0.15<ref name="Battle2022"/>
| spectral_type = [[X-type asteroid|Xn]] or [[S-type asteroid|S]]<ref name="Battle2022"/>
| abs_magnitude = {{val|15.72|0.02}}<ref name="Husarik2022"/><br/>16.04<ref name="jpldata"/><ref name="MPC-object"/>
}}

'''{{mp|(52768) 1998 OR|2}}''' ([[provisional designation]] '''{{mp|1998 OR|2}}''') is an [[asteroid]] on an [[eccentric orbit]], classified as a [[near-Earth object]] and [[potentially hazardous asteroid]] of the [[Amor asteroid|Amor group]], with a diameter of {{convert|2|km|mi|sp=us}}. It was discovered on 24 July 1998, by astronomers of the [[Near-Earth Asteroid Tracking]] (NEAT) program at the [[Haleakala Observatory]], Hawaii, it passed very near to earth on 29 April 2020 at around 4:15am<ref name="MPC-object" />. It is one of the brightest and therefore largest potentially hazardous asteroids known to exist.<ref name="MPC-PHA-list" /> With an [[observation arc]] of 35 years, the asteroid has a well-determined orbit, and its trajectory is well known through the year 2197.<ref name="jpldata" /> The asteroid's orbit is only potentially hazardous on a time scale of thousands of years.<ref name="PeterThomas"/>

== Orbit and classification ==
{{multiple image|perrow = 1

| align = left
| direction = vertical
| total_width = 200

| image1 = Asteroid 52768 (1998 OR2) 09.04.2020.gif
| width1 = 
| caption1 = Time lapse of asteroid {{mp|1998 OR|2}}'s motion in the sky on 9 April 2020

| image2 = 52768 1998 OR2.jpg
| width2 = 
| caption2 = Orbit diagram of {{mp|1998 OR|2}}

| image3 = 1998OR2 apr19 mosaic.png
| width3 = 
| caption3 = Arecibo radar images of {{mp|1998 OR|2}} taken over a two-hour period in April 2020

| image4 = Animation of 1998 OR2 close approach in 2020.gif
| width4 = 
| caption4 = Animation of 1998 OR2 close approach in 2020
}}

{{mp|1998 OR|2}} is a member of the dynamical [[Amor asteroid|Amor group]] of [[near-Earth asteroid]]s,<ref name="jpldata" /><ref name="MPC-object" /> 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 [[Perturbation (astronomy)|perturbations]] of its orbit.

It orbits the Sun at a distance of 1.0–3.7 [[Astronomical unit|AU]] once every 3 years and 8 months (1,344 days; [[semi-major axis]] of 2.38 AU). Its orbit has a high [[orbital eccentricity|eccentricity]] of 0.57 and an [[orbital inclination|inclination]] of {{formatnum:6}}° 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 AU.<ref name="jpldata" />

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.<ref name="MPC-object" />

=== Close approaches ===
With an [[absolute magnitude]] of approximately 15.8,<ref name="MPC-object" /> {{mp|1998 OR|2}} is one of the brightest and presumably largest-known [[potentially hazardous asteroid]]s (see [[Potentially hazardous asteroid#Largest PHA|PHA-list]]).<ref name="MPC-PHA-list" /> It currently has an Earth [[minimum orbital intersection distance]] of {{convert|0.0087|AU|km|abbr=on|lk=off|sigfig=3}}, which translates into 3.4 [[Lunar distance (astronomy)|lunar distances]] (LD).<ref name="jpldata" /> On 16 April 2079, this asteroid will make a near-Earth encounter at a safe distance of {{convert|0.0118|AU|LD|sigfig=3|abbr=on}}, and pass the Moon at {{convert|0.0092|AU|LD|sigfig=2|abbr=on}}.<ref name="jpldata" /> 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 {{convert|0.042|AU|e6km LD|sigfig=2|abbr=unit|lk=on}} from Earth.<ref name="jpldata" /> 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 ±6 km.<ref name=uncertainty>[https://archive.today/20200429151604/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1998OR2;cad=1 JPL #277 (solution date: 2020-Apr-29)] (MaxDist of 0.0420485754979265) – (MinDist of 0.0420484977243086) * [[Astronomical unit|149597870.7]] = 12 km</ref> (For comparison, [[Venus]] will be {{convert|0.29|AU|e6km LD|sigfig=2|abbr=unit|lk=on|disp=or}} from Earth on 3 June 2020.)

{{clear|left}}
{{Large near earth asteroid flybys 5LD}}

== Physical characteristics ==
[[File:1998 OR2 Radar.gif|left|thumb|upright|Animation of radar images showing {{mp|1998 OR|2}}'s rotation]]
According to observations by the [[NASA IRTF telescope]] during the ExploreNEOs Warm Spitzer program, {{mp|1998 OR|2}} is a rather rare [[L-type asteroid]].<ref name="Thomas-2014" /> Delay-Doppler radar observations by the [[Arecibo Observatory]] in April 2020 have shown that {{mp|1998 OR|2}} bears a large, crater-like concavity in its shape.<ref name="naic" /> These radar observations have also resolved several other topographic features on the asteroid's surface, such as hills and ridges.<ref name="ucf"/>

=== Rotation period ===
In 2009, rotational [[lightcurve]]s of {{mp|1998 OR|2}} were obtained from [[Photometry (astronomy)|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 (astronomy)|magnitude]], respectively ({{small|[[LCDB quality code|U=2/2+]]}}).<ref name="Betzler-2009c" /><ref name="Koehn-2014" /> The latter rotation period of 4.1 hours was later confirmed by radar observations of the asteroid in 2020.<ref name="ucf" /><ref name="naic" />

=== Diameter and albedo ===
The Collaborative Asteroid Lightcurve Link (CALL) assumes a standard [[astronomical albedo|albedo]] for stony asteroids of 0.20 and calculates a diameter of {{cvt|2.15|km|mi}} based on an [[absolute magnitude]] of 15.7.<ref name="lcdb" /> It is the first near-earth asteroid to show evidence of [[Meteorite shock stage|shock darkening]]: the slow darkening of the surface over time, from micrometeorites and solar wind.<ref name="Battle2022"/>

== Naming ==
As of 2023, this [[minor planet]] has not been [[List of named minor planets (alphabetical)|named]].<ref name="MPC-object" />

== Notes ==
{{notelist}}

== References ==
{{reflist|30em|refs=

<ref name="jpldata">{{cite web
|type = 2022-12-26 last obs.
|title = Small-Body Database Lookup: 52768 (1998 OR2)
|url = https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=52768&view=OPDCA
|publisher = [[Jet Propulsion Laboratory]]
|accessdate = 5 April 2023}}</ref>

<ref name="MPC-object">{{cite web
|title = 52768 (1998 OR2)
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=52768
|accessdate = 7 March 2020}}</ref>

<ref name="MPC-PHA-list">{{cite web
|title = List of the Potentially Hazardous Asteroids (PHAs)
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/iau/lists/t_phas.html
|accessdate = 24 January 2018}}</ref>

<ref name="lcdb">{{cite web
|title = LCDB Data for (52768)
|publisher = Asteroid Lightcurve Database (LCDB)
|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=52768%7C
|accessdate = 7 March 2020}}</ref>

<ref name="coordstransform">{{cite web
|title = Coordinate transformations
|url = https://aas.aanda.org/articles/aas/full/1998/01/ds1449/node3.html
|work = Astronomy and Astrophysics
|publisher = European Southern Observatory
|date = January 1998
|accessdate = 5 April 2023
|archive-date = 17 June 2021
|archive-url = https://web.archive.org/web/20210617050235/https://aas.aanda.org/articles/aas/full/1998/01/ds1449/node3.html
|url-status = live}}</ref>

<ref name="Koehn-2014">{{Cite journal
|display-authors = 6
|first1 = Bruce W. |last1 = Koehn
|first2 = Edward G. |last2 = Bowell
|first3 = Brian A. |last3 = Skiff
|first4 = Jason J. |last4 = Sanborn
|first5 = Kyle P. |last5 = McLelland
|first6 = Petr |last6 = Pravec
|first7 = Brian D. |last7 = Warner
|date = October 2014
|title = Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) - 2009 January through 2009 June
|journal = The Minor Planet Bulletin
|volume = 41
|issue = 4
|pages = 286–300
|issn = 1052-8091
|bibcode = 2014MPBu...41..286K
}}</ref>

<ref name="Betzler-2009c">{{Cite journal
|first1 = Alberto Silva |last1 = Betzler
|first2 = Alberto Brum |last2 = Novaes
|date = October 2009
|title = Photometric Observations of 1998 OR2, 1999 AQ10, and 2008 TC3
|journal = The Minor Planet Bulletin
|volume = 36
|issue = 4
|pages = 145–147
|issn = 1052-8091
|bibcode = 2009MPBu...36..145B
}}</ref>

<ref name="Thomas-2014">{{cite journal
|first1 = Cristina A. |last1 = Thomas
|first2 = Joshua P. |last2 = Emery
|first3 = David E. |last3 = Trilling
|first4 = Marco |last4 = Delbó
|first5 = Joseph L. |last5 = Hora
|first6 = Michael |last6 = Mueller
|date = January 2014
|title = Physical characterization of Warm Spitzer-observed near-Earth objects
|journal = Icarus
|volume = 228
|pages = 217–246
|bibcode = 2014Icar..228..217T
|doi = 10.1016/j.icarus.2013.10.004
|arxiv = 1310.2000
|s2cid = 119278697
}}</ref>

<ref name="naic">{{cite news
|title = Arecibo Continues Operations through Pandemic to Observe Potentially Hazardous Asteroid 1998 OR2
|url = http://www.naic.edu/~pradar/press/1998OR2.php
|first = A. K. |last = Virkki
|work = Planetary Radar Science Group
|publisher = NAIC-Arecibo Observatory
|date = 23 April 2020
|accessdate = 23 April 2020}}</ref>

<ref name="ucf">{{cite news
|title = Asteroid Visiting Earth's Neighborhood Brings its Own Face Mask
|url = https://www.ucf.edu/news/asteroid-visiting-earths-neighborhood-brings-its-own-face-mask/
|first = Zenaida Gonzalez |last = Kotala
|work = UCF Today
|publisher = University of Central Florida
|date = 23 April 2020
|accessdate = 23 April 2020}}</ref>

<ref name="PeterThomas">[https://twitter.com/ptastro1/status/1264004040498634752 1998OR2 MOID over the next 2700 years] – Peter Thomas</ref>

<ref name="Husarik2022">{{cite conference
|first1 = Marek |last1 = Husárik
|first2 = Oleksandra |last2 = Ivanova
|title = Photometric results of two PHAs: (52768) 1998 OR2 and (99942) Apophis
|url = https://meetingorganizer.copernicus.org/EPSC2022/EPSC2022-671.html
|date = September 2021
|conference = 16th Europlanet Science Congress 2022
|publisher = Europlanet Society
|volume = 16
|id = EPSC2022-671
|location = Granada, Spain
|doi = 10.5194/epsc2022-671
|bibcode = 2022EPSC...16..671H
|doi-access = free
}}</ref>

<ref name="Battle2022">{{cite journal
|first1 = Adam |last1 = Battle
|first2 = Vishnu |last2 = Reddy
|first3 = Juan A. |last3 = Sanchez
|first4 = Benjamin |last4 = Sharkey
|first5 = Neil |last5 = Pearson
|first6 = Bryn |last6 = Bowen
|title = Physical Characterization of Near-Earth Asteroid (52768) 1998 OR2: Evidence of Shock Darkening/Impact Melt
|journal = The Planetary Science Journal
|date = September 2022
|volume = 3
|issue = 9
|id = 226
|pages = 13
|doi-access = free
|doi = 10.3847/PSJ/ac7223
|arxiv = 2210.03049
|bibcode = 2022PSJ.....3..226B}}</ref>

<ref name="PDC-Devogele2023">{{cite conference
|display-authors = etal
|first1 = Maxime |last1 = Devogèle
|title = (52768) 1998 OR2, an analog to (16) Psyche in the near-Earth space?
|url = https://az659834.vo.msecnd.net/eventsairwesteuprod/production-atpi-public/e074728cee8b449aba50cfe4962792a0
|conference = 8th IAA Planetary Defense Conference
|location = Vienna, Austria
|date = 5 April 2023
|pages = 9
|archive-url = https://web.archive.org/web/20230405225714/https://az659834.vo.msecnd.net/eventsairwesteuprod/production-atpi-public/e074728cee8b449aba50cfe4962792a0
|archive-date = 5 April 2023
|url-status = live}}</ref>

}} 

== External links ==
* [http://www.minorplanet.info/PHP/lcdbsummaryquery.php Asteroid Lightcurve Database (LCDB)], query form ([http://www.minorplanet.info/lightcurvedatabase.html info] {{Webarchive|url=https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html |date=16 December 2017 }})
* [http://obswww.unige.ch/~behrend/page_cou.html Asteroids and comets rotation curves, CdR] – Observatoire de Genève, Raoul Behrend
* {{NeoDys|52768}}
* {{ESA-SSA|52768|1998OR2}}
* {{JPL small body|id=2052768}}

{{Minor planets navigator |52767 Ophelestes |number=52768 | }}
{{Small Solar System bodies}}
{{2020 in space}}
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{{DEFAULTSORT:1998 OR2}}
[[Category:Amor asteroids|052768]]
[[Category:Discoveries by NEAT|052768]]
[[Category:Potentially hazardous asteroids|052768]]
[[Category:Astronomical objects discovered in 1998|19980724]]
[[Category:Near-Earth objects in 2020|20200429]]
[[Category:Radar-imaged asteroids|052768]]
[[Category:X-type asteroids|052768]]

Wikipedia - User contributions [en]

(52768) 1998 OR2