{{Short description|Near-Earth asteroid in 2040}} {{DISPLAYTITLE:{{mp|(367789) 2011 AG|5}}}} {{Use dmy dates|date=October 2019}} {{Infobox planet | minorplanet = yes | name = {{mp|(367789) 2011 AG|5}} | background = #FFC2E0 | image = 2011 AG5 Goldstone radar 2023-02-04 anim.gif | image_scale = | caption = Animation of {{mp|2011 AG|5}} rotating in radar images by the Goldstone Solar System Radar on 4 February 2023 | discovery_ref = <ref name="jpldata" /><ref name="MPEC2011-A31"/> | discoverer = Mount Lemmon Srvy. | discovery_site = Mount Lemon Obs. | discovered = 8 January 2011 | mpc_name = {{mp|(367789) 2011 AG|5}} | alt_names = | pronounced = | named_after = <!--xafter<br />{{small|()}}<ref name="" />--> | mp_category = {{nowrap|Apollo{{·}}NEO{{·}}PHA<ref name="jpldata"/><ref name="MPC-object" />}} | orbit_ref = <ref name="jpldata" /> | epoch = 2023-Feb-25 (JD 2460000.5) | uncertainty = 0 | observation_arc = 14.2 yr (5,201 days) | earliest_precovery_date = 3 October 2008 | aphelion = 1.978 AU | perihelion = 0.87066 AU | time_periastron = 2023-Mar-17 | semimajor = 1.424 AU | eccentricity = 0.3887 | period = 1.7 yr (620.9 days) | mean_anomaly = 348.2° | mean_motion = {{Deg2DMS|0.575895|sup=ms}} / day | inclination = 3.6946° | asc_node = 135.6° | arg_peri = 54.02° | moid = {{cvt|0.00038|AU|km LD|lk=out}} | dimensions = {{val|140|ul=m}}<ref name=summary/> | mass = {{val|4|e=9|ul=kg}} {{small|(assumed)}}<ref name=summary/> | rotation = | albedo = | spectral_type = | abs_magnitude = 21.9<ref name="MPC-object"/><ref name="jpldata"/> }}
'''{{mp|(367789) 2011 AG|5}}''' is a sub-kilometer asteroid, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group.<ref name=jpldata/> It has a diameter of about {{convert|140|m|sp=us}}.<ref name=summary/> It was removed from the Sentry Risk Table on 21 December 2012 and as such it now has a rating of 0 on the Torino Scale.<ref name="removed"/> It was recovered in December 2022 extending the observation arc from 4.8 years to 14 years. As of 2023, the distance between the orbits of Earth and {{mp|2011 AG|5}} is {{cvt|0.0004|AU|km LD|lk=on}}<ref name="jpldata"/>
{| class="wikitable" style="font-size: 0.9em;" |+Earth Approaches on 3 February 2023 and 4 February 2040<ref name=jpldata/> ! Date ! JPL Horizons<br />nominal geocentric<br />distance (AU) ! uncertainty<br />region<br />(3-sigma) |- |2023-Feb-03 08:51 ± 00:01 ||{{Convert|0.01215|AU|e6km|abbr=unit|lk=on}}<ref name="jpldata"/> || ±{{val|112|u=km}}<ref name="CA2023"/> |- |2040-Feb-04 08:29 ± 00:06 ||{{Convert|0.00725|AU|e6km|abbr=unit|lk=on}}<ref name="jpldata"/> || ±{{val|5800|u=km}}<ref name="CA2040"/> |}
== Description == left|thumb|Orbital diagram of {{mp|2011 AG|5}} (green) passing the Earth-Moon system in February 2040 (orbital solution from 2011)
{{mp|2011 AG|5}} was discovered on 8 January 2011 by the Mount Lemmon Survey at an apparent magnitude of 19.6 using a {{convert|1.52|m|in|adj=on|sp=us}} reflecting telescope.<ref name="MPC-object" /><ref name="MPEC2011-A31"/> Pan-STARRS precovery images from 8 November 2010 extended the observation arc to 317 days. Observations by the Gemini {{convert|8.2|m|in|adj=on}} telescope at Mauna Kea recovered the asteroid on 20, 21 and 27 October 2012,<ref name="news176"/> and extended the observation arc to 719 days.<ref name="MPC-object" />
The October 2012 observations reduced the orbit uncertainties by more than a factor of 60, meaning that the Earth's position in February 2040 no longer falls within the range of possible future paths for the asteroid.<ref name="news176"/> On 4 February 2040 the asteroid will pass no closer than {{convert|0.007|AU|km mi|abbr=on|lk=on}} (~2.8 LD) from Earth.<ref name=jpldata/> Until 21 December 2012 it was listed on the Sentry Risk Table with a rating on the Torino Scale of Level 1.<ref name="removed"/> A Torino rating of 1 is a routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger.<ref name="Torino-scale"/> It is estimated that an impact would produce the equivalent of 100 megatons of TNT,<ref name=summary/> roughly twice that of the most powerful nuclear weapon ever detonated (Tsar Bomba). This is powerful enough to damage a region at least a hundred miles wide.{{fact|date=August 2025}}
=== Older risks === Virtual clones of the asteroid that fit the mid-2012 uncertainty region in the known trajectory showed four potential impacts between 2040 and 2047.<ref name=summary/> It had a 1 in 500 chance of impacting the Earth on 5 February 2040.<ref name=summary/> In September 2013, there was an opportunity to make additional observations of {{mp|2011 AG|5}} when it came within {{convert|0.98|AU|km mi|abbr=on|lk=off}} of Earth.<ref name="NASA2012-051"/> The 2013 observations allowed a further refinement to the known trajectory. The asteroid will also pass {{convert|0.0121|AU|km mi|abbr=on|lk=off}} from the Earth on 3 February 2023.<ref name=jpldata/><ref name="NEODyS"/> The 2023 gravitational keyhole was 227 miles (365 kilometers) wide.<ref name="NASA2012-178"/> With a Palermo scale rating of -1.00,<ref name=summary/> the odds of impact by {{mp|2011 AG|5}} were about 10 times less<ref name=math/> than the background hazard level of Earth impacts which is defined as the average risk posed by objects of the same size or larger over the years until the date of the potential impact.<ref name="palermo"/>
== References == <references>
<ref name="jpldata">{{cite web |title = JPL Small-Body Database Browser: 367789 (2011 AG5) |publisher = Jet Propulsion Laboratory |url = https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=367789&view=OPC |archive-url=https://archive.today/20221024145712/https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html%23/?sstr=367789&view=OPC |archive-date=2022-10-24 |url-status=live |accessdate = 1 January 2023}}</ref>
<ref name="removed">{{cite web |title=Date/Time Removed |publisher=NASA/JPL Near-Earth Object Program Office |url=http://neo.jpl.nasa.gov/risk/removed.html |archive-url=https://web.archive.org/web/20130108122117/http://neo.jpl.nasa.gov/risk/removed.html |url-status=dead |archive-date=2013-01-08 |accessdate=2012-12-21}}</ref>
<ref name="MPEC2011-A31">{{Cite web |title=MPEC 2011-A31 : 2011 AG5 |publisher=IAU Minor Planet Center |date=2011-01-09 |url=https://www.minorplanetcenter.net/mpec/K11/K11A31.html |accessdate=2011-10-17}} (K11A05G)</ref>
<ref name="MPC-object">{{cite web |title = 367789 (2011 AG5) |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=367789 |accessdate = 17 January 2018}}</ref>
<ref name="news176">{{cite web |date=21 December 2012 |title="All Clear" Given on Potential 2040 Impact of Asteroid 2011 AG5 |publisher=NASA/JPL Near-Earth Object Program Office |url=http://neo.jpl.nasa.gov/news/news176.html |archive-url=https://web.archive.org/web/20121231004831/http://neo.jpl.nasa.gov/news/news176.html |url-status=dead |archive-date=31 December 2012 |accessdate=2012-12-21}}</ref>
<ref name="Torino-scale">{{cite web |date=13 April 2005 |title=The Torino Impact Hazard Scale |publisher=NASA/JPL Near-Earth Object Program Office |url=http://neo.jpl.nasa.gov/torino_scale1.html |archive-url=https://web.archive.org/web/20041230031246/http://neo.jpl.nasa.gov/torino_scale1.html |url-status=dead |archive-date=30 December 2004 |accessdate=2011-11-05}}</ref>
<ref name="NEODyS">{{cite web |title=NEODyS-2 Close Approaches for 2011AG5 |publisher=Near Earth Objects - Dynamic Site |url=http://newton.spacedys.com/neodys/index.php?pc=1.1.8&n=2011AG5 |accessdate=2013-09-21}}</ref>
<ref name=summary>{{cite web |title=Earth Impact Risk Summary: 2011 AG5 |publisher=Wayback Machine: NASA/JPL Near-Earth Object Program Office |url=http://neo.jpl.nasa.gov/risk/2011ag5.html |accessdate=2012-12-12 |url-status=dead |archiveurl=https://web.archive.org/web/20121118232754/http://neo.jpl.nasa.gov/risk/2011ag5.html |archivedate=2012-11-18}}</ref>
<ref name="NASA2012-051">{{cite web |date=28 February 2012 |title=Asteroid 2011 AG5 - A Reality Check |publisher=NASA/JPL Near-Earth Object Program Office |url=http://www.jpl.nasa.gov/news/news.cfm?release=2012-051 |accessdate=29 February 2012 |archive-date=16 April 2021 |archive-url=https://web.archive.org/web/20210416083943/https://www.jpl.nasa.gov/news/news.cfm?release=2012-051 |url-status=dead }}</ref>
<ref name="NASA2012-178">{{cite web |date=15 June 2012 |title=NASA Releases Workshop Data and Findings on Asteroid 2011 AG5 |publisher=NASA/JPL |url=http://www.nasa.gov/mission_pages/asteroids/news/asteroid20120615.html |accessdate=2012-06-16}} [http://www.jpl.nasa.gov/news/news.cfm?release=2012-178 (2012-178)]</ref>
<ref name=math>Math: 10<sup>1.00</sup> = 10</ref>
<ref name="palermo">{{cite web |date=31 August 2005 |title=The Palermo Technical Impact Hazard Scale |publisher=NASA/JPL Near-Earth Object Program Office |url=http://neo.jpl.nasa.gov/risk/doc/palermo.html |archive-url=https://web.archive.org/web/20020321092747/http://neo.jpl.nasa.gov/risk/doc/palermo.html |url-status=dead |archive-date=21 March 2002 |accessdate=2011-10-14}}</ref>
<ref name="CA2023">{{cite web |title=Horizons Batch for 2023-02-03 Close Approach |publisher=JPL Horizons |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272011+AG5%27&START_TIME=%272023-02-03%2008:51%27&STOP_TIME=%272023-02-04%27&STEP_SIZE=%271%20day%27&QUANTITIES=%2720,39%27 |archive-url=https://web.archive.org/web/20221024142219/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272011+AG5%27&START_TIME=%272023-02-03%2008:50%27&STOP_TIME=%272023-02-04%27&STEP_SIZE=%271%20day%27&QUANTITIES=%2720,39%27 |archive-date=2022-10-24 |url-status=live |accessdate=2023-01-01}} RNG_3sigma = uncertainty range in km. (JPL#63/Soln.date: 2021-Jul-11 generates RNG_3sigma = {{val|1518|u=km}})</ref>
<ref name="CA2040">{{cite web |title=Horizons Batch for 2040-02-04 Close Approach |publisher=JPL Horizons |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272011+AG5%27&START_TIME=%272040-02-04%2008:29%27&STOP_TIME=%272040-02-05%27&STEP_SIZE=%271%20day%27&QUANTITIES=%2720,39%27 |archive-url=https://web.archive.org/web/20221024141438/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%25272011+AG5%2527&START_TIME=%25272040-02-04%252008:49%2527&STOP_TIME=%25272040-02-05%2527&STEP_SIZE=%25271%2520day%2527&QUANTITIES=%252720,39%252 |archive-date=2022-10-24 |url-status=live |accessdate=2023-01-01}} RNG_3sigma = uncertainty range in km. (JPL#63/Soln.date: 2021-Jul-11 generates RNG_3sigma = {{val|78079|u=km}})</ref>
</references> <!-- end of reflist -->
== External links == * [http://www.ifa.hawaii.edu/info/press-releases/allclear2011AG5.shtml UH Observations Result in "All Clear" for Potential Asteroid Impact] (Institute for Astronomy at the University of Hawaii 21 December 2012) * [http://www.slate.com/blogs/bad_astronomy/2012/12/22/asteroid_impact_avoided_near_earth_rock_will_miss_in_2040.html Phew! One Less Asteroid Impact to Worry About] (Phil Plait 22 Dec. 2012) * [http://www.brera.mi.astro.it/sormano/teca.html Table of next close approaches] (Sormano Astronomical Observatory) * [http://www.brera.mi.astro.it/sormano/mbpl.html MBPL - Minor Body Priority List] (Sormano Astronomical Observatory) * {{NeoDys|367789}} * {{ESA-SSA|367789|2011AG5}} * {{JPL small body}}
{{Minor planets navigator | |number=367789 |PageName={{mp|(367789) 2011 AG|5}} | }} {{Small Solar System bodies}} {{2011 in space}} {{2023 in space}} {{Authority control}}
{{DEFAULTSORT:2011 AG5}} 367789 367789 367789 367789 20110108 20230203 20110108