| observation_arc = 2.65 years<br>(last seen 2014)
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{{Infobox planet |
{{Infobox planet |
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| |
| minorplanet = yes |
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| |
| name = 2011 MD |
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| background = #FFC2E0 |
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| name=2011 MD |
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| image= |
| image = PIA18453-Asteroid2011MD-SpitzerSpaceTelescope-IRAC-Feb2014.jpg |
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| image_scale = |
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| caption=2011MD in February 2014<br>([[Spitzer Space Telescope|Spitzer Space Telescope, IRAC]]). |
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| caption = {{mp|2011 MD}} imaged by ''[[Spitzer Space Telescope|Spitzer]]'' in February 2014 |
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| discovery_ref = <ref name="MPEC2011-M23"/> |
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| discovery_ref = <ref name="jpldata" /><ref name="MPEC2011-M23"/> |
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| discoverer= [[Lincoln Near-Earth Asteroid Research|LINEAR]] ([[List of observatory codes#700-799|704]]) |
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| discoverer = [[Lincoln Near-Earth Asteroid Research|LINEAR]] |
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| discovered= 2011 June 22 |
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| discovery_site = [[Lincoln Laboratory's Experimental Test Site|Lincoln Lab's ETS]] |
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| alt_names= |
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| discovered = 2011 June 22<br />{{small|(first observed only)}} |
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| mp_category=[[Amor asteroid|Amor]] [[Near-Earth object|NEO]]<ref name="jpldata"/> |
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| mpc_name = 2011 MD |
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| epoch = 2012-Sep-30<br>([[Uncertainty Parameter U|Uncertainty]]=2)<ref name=jpldata/> |
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| alt_names = |
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| observation_arc = 2.65 years<br>(last seen 2014) |
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| |
| pronounced = |
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| |
| named_after = |
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| mp_category = {{nowrap|[[Near-Earth object|NEO]]{{·}}[[Apollo asteroid|Apollo]]<ref name="jpldata"/>{{·}}[[Amor asteroid|Amor]]<ref name="MPC-object" />}} |
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| aphelion = 1.095 [[Astronomical Unit|AU]] |
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| orbit_ref = <ref name="jpldata" /> |
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| eccentricity = 0.0370 |
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| |
| epoch = 13 July 2011 ([[Julian day|JD]] 2455755.5) |
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| uncertainty = 2<ref name="jpldata" />{{·}}0<ref name="MPC-object" /> |
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| inclination = 2.445[[Degree (angle)|°]] |
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| observation_arc = 2.65 yr (967 days) |
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| asc_node = 271.6° |
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| aphelion = 1.1031 [[Astronomical unit|AU]] |
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| arg_peri = 5.838° |
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| |
| perihelion = 1.0161 AU |
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| semimajor = 1.0596 AU |
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| dimensions = ~{{convert|6|m|0|sp=us}}<ref name="NASA2014-195"/><br>7 - 15 meters<ref name="MPC-H">{{cite web |
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| eccentricity = 0.0411 |
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|title=Conversion of Absolute Magnitude to Diameter |
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| period = 1.09 [[Julian year (astronomy)|yr]] (398 days) |
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|publisher=[[Minor Planet Center]] |
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| mean_anomaly = 11.051[[Degree (angle)|°]] |
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|url=http://www.minorplanetcenter.net/iau/lists/Sizes.html |
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| mean_motion = {{Deg2DMS|0.9037|sup=ms}} / day |
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|accessdate=2012-05-30}}</ref> |
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| inclination = 2.5624° |
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| density=~1 g/cm³ ([[rubble pile]])<ref name="NASA2014-195"/> |
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| asc_node = 273.96° |
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| rotation = 0.1937 h<ref name="jpldata"/> |
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| arg_peri = 4.6748° |
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| abs_magnitude = 28.1<ref name="jpldata"/> |
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| moid = 0.0003 AU (0.1 [[Lunar distance (astronomy)|LD]]) |
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| mean_diameter = {{val|6|ul=m}} {{small|(estimate)}}<ref name="NASA2014-195"/><ref name="Mommert2014"/> |
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| density = {{val|1|ul=g/cm3}} {{small|(est. [[rubble pile]])}}<ref name="NASA2014-195"/> |
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| albedo = 0.3<ref name="Mommert2014"/> |
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| rotation = {{val|0.1937|ul=h}}<ref name="jpldata"/> |
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| abs_magnitude = 28.0<ref name="jpldata"/> |
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}} |
}} |
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'''2011 MD''' is a bright micro-[[asteroid]], classified as [[near-Earth object]] of the [[Apollo asteroid|Apollo]] and [[Amor asteroid|Amor group]], respectively.<ref name="jpldata"/><ref name="MPC-object" /> On 27 June 2011, at around 17:00 UTC (13:00 EDT), the object passed exceptionally close to Earth's surface at a distance of approximately {{convert|12000|km|mi|-2|sp=us}}, roughly the diameter of the Earth.<ref name="NASA-news" /><ref name="SKY1"/><ref name="NatGeo" /> |
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'''2011 MD''' is an [[List of Apollo asteroids|Apollo asteroid]] that passed relatively close to Earth's surface — at a distance of about {{convert|12000|km|mi|-2|sp=us}}, roughly the diameter of the Earth — at around 17:00 UTC (13:00 EDT) on June 27, 2011.<ref name="jpldata"/><ref>{{cite web |author= Don Yeomans & Paul Chodas |url= http://neo.jpl.nasa.gov/news/news172.html |title= Bend it Like Beckham! Small Asteroid to Whip Past Earth on June 27, 2011 |publisher= [[NASA]]/JPL Near-Earth Object Program Office |date= June 23, 2011 |accessdate= June 26, 2011 | archiveurl= http://web.archive.org/web/20110704093604/http://neo.jpl.nasa.gov/news/news172.html| archivedate= 4 July 2011 <!--DASHBot-->| deadurl= no}}</ref><ref name="SKY1"/><ref>{{cite web | url=http://news.nationalgeographic.com/news/2011/06/110627-asteroid-earth-close-pass-weiss-moon-space-science/ | title=Asteroid Just Buzzed Earth—Came Closer Than the Moon}}</ref> Although the object was initially believed to be [[space debris|space junk]], subsequent observations confirmed that it is an [[asteroid]].<ref name="SKY1" /> |
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== Description == |
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A few hours before the asteroid's nearest approach in 2011, it appeared close to the Sun, so observations were possible for only a brief period. Backyard astronomers were able to observe it with telescopes from Australia, southern Africa, and the Americas.<ref name="SKY1" /> |
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[[File:2011 MD on Jun 26.jpg|thumb|left|{{mp|2011 MD}} on 26 June 2011]] |
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Although {{mp|2011 MD}} was initially believed to be [[space debris|space junk]], subsequent observations confirmed that it is an asteroid. A few hours before the asteroid's nearest approach in 2011, it appeared close to the Sun, so observations were possible for only a brief period. Backyard astronomers were able to observe it with telescopes from Australia, southern Africa, and the Americas.<ref name="SKY1" /> |
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==Overview== |
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[[File:2011 MD on Jun 26.jpg|thumb|250px|left|2011MD on 26 June 2011]] |
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{{mp|2011 MD}} was discovered on 22 June 2011, by astronomers of the [[Lincoln Near-Earth Asteroid Research]] (LINEAR) at the U.S. [[Lincoln Laboratory Experimental Test Site]]inSocorro, New Mexico, by a pair of robotic telescopes. According to original rough estimates, the asteroid's length was between {{convert|10|and|45|m|ft|-1|sp=us}}.<ref name="MPC-object" /><ref name="MANIA"/> However, according to the more recent [[Absolute magnitude#Solar System bodies (H)|absolute magnitude]] (H) measurement of 28.1<ref name="jpldata"/> and its albedo of 0.3, the asteroid is closer to 6 meters or 20 feet in diameter.<ref name="Mommert2014"/> |
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Emily Baldwin of ''[[Astronomy Now]]'' said that there was no threat of collision, and should the asteroid enter [[Earth's atmosphere]], it would "mostly burn up in a brilliant fireball, possibly scattering a few [[meteorite]]s", causing no likely harm to life or property on the ground.<ref name="MANIA" /> |
Emily Baldwin of ''[[Astronomy Now]]'' said that there was no threat of collision, and should the asteroid enter [[Earth's atmosphere]], it would "mostly burn up in a brilliant fireball, possibly scattering a few [[meteorite]]s", causing no likely harm to life or property on the ground.<ref name="MANIA" /> |
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The |
The 27 June 2011 close approach to Earth increased the orbital period of {{mp|2011 MD}} from 380 days to 396 days. During close approach the asteroid passed Earth at a relative speed of 6.7 km/s<ref name=jpldata/> with a [[geocentric]] eccentricity of 1.1. |
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2011 MD was observed by the [[Spitzer Space Telescope]] in February 2014 and estimated to be {{convert|6|m|0|sp=us}} in diameter.<ref name="NASA2014-195"/> The asteroid is a [[porous]] [[rubble pile]] with a density similar to water.<ref name="NASA2014-195"/> On June |
{{mp|2011 MD}} was observed by the [[Spitzer Space Telescope]] in February 2014 and estimated to be {{convert|6|m|0|sp=us}} in diameter.<ref name="NASA2014-195"/> The asteroid is a [[porous]] [[rubble pile]] with a density similar to water.<ref name="NASA2014-195"/>On19 June 2014, NASA reported that asteroid {{mp|2011 MD}} was a prime candidate for [[Asteroid capture|capture]] by the [[Asteroid Redirect Mission]] (ARM) in the early 2020s.<ref name="AP-20140619" /> |
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{| class=wikitable |
{| class=wikitable style="font-size: 0.9em;" |
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|- valign=top |
|- valign=top |
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!Parameter |
!Parameter |
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![[ |
![[Epoch (astronomy)|Epoch]] |
||
! [[Apsis|aphelion]]< |
! [[Apsis|aphelion]]<br />(Q) |
||
! [[Apsis|perihelion]]< |
! [[Apsis|perihelion]]<br />(q) |
||
! [[Semi-major axis|Semi-major< |
! [[Semi-major axis|Semi-major<br />axis]]<br />(a) |
||
! [[Orbital eccentricity|eccentricity]]< |
! [[Orbital eccentricity|eccentricity]]<br />(e) |
||
! [[Orbital period|Period]]< |
! [[Orbital period|Period]]<br />(p) |
||
! [[Orbital inclination|inclination]]< |
! [[Orbital inclination|inclination]]<br />(i) |
||
! [[Longitude of the ascending node|Longitude< |
! [[Longitude of the ascending node|Longitude<br />ascending<br />node]]<br />(Ω) |
||
! [[Mean anomaly|Mean< |
! [[Mean anomaly|Mean<br />anomaly]]<br />(M) |
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! [[Argument of periapsis|Argument< |
! [[Argument of periapsis|Argument<br />of<br />perihelion]]<br />(ω) |
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|- valign=top |
|- valign=top |
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! Units |
! Units |
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! |
! |
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!colspan=3|[[Astronomical unit|AU]] |
!colspan=3|[[Astronomical unit|AU]] |
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! — |
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! |
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! (days) |
! (days) |
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!colspan=4| (°) |
!colspan=4| (°) |
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|} |
|} |
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== |
=== Gallery === |
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{{multiple image |
{{multiple image |
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| header = |
| header = |
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| align = |
| align = left |
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| direction = horizontal |
| direction = horizontal |
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| total_width = 900 |
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| image1 = Trajectory of near-Earth asteroid 2011 MD 1.gif |
| image1 = Trajectory of near-Earth asteroid 2011 MD 1.gif |
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| width1 = |
| width1 = |
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| alt1 = |
| alt1 = |
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| caption1 = Trajectory of 2011 MD projected onto the Earth's orbital plane. Note, from this viewing angle, the asteroid passes underneath the Earth. |
| caption1 = Trajectory of {{mp|2011 MD}} projected onto the Earth's orbital plane. Note, from this viewing angle, the asteroid passes underneath the Earth. |
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| image2 = Trajectory of near-Earth asteroid 2011 MD 2.gif |
| image2 = Trajectory of near-Earth asteroid 2011 MD 2.gif |
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| width2 = |
| width2 = |
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| alt2 = |
| alt2 = |
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| caption2 = Trajectory of 2011 MD from the general direction of the Sun. |
| caption2 = Trajectory of {{mp|2011 MD}} from the general direction of the Sun. |
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| footer = |
| footer = |
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| image3 = Spacious Structure of Asteroid 2011 MD (Artist's Concept).jpg |
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| width3 = |
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| alt3 = |
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| caption3 = Artist's concept of spacious structure of asteroid 2011 MD<ref>{{cite web |title=The Spacious Structure of Asteroid 2011 MD (Artist's Concept) |url=https://www.jpl.nasa.gov/images/pia18456-the-spacious-structure-of-asteroid-2011-md-artists-concept |website=NASA Jet Propulsion Laboratory (JPL) |access-date=13 April 2022}}</ref> |
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}} |
}} |
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{{clear|left}} |
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==See also== |
== See also == |
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* [[Asteroid capture]] |
* [[Asteroid capture]] |
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* [[Asteroid Redirect Mission]] |
* [[Asteroid Redirect Mission]] |
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* [[Near-Earth Object]] |
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==References== |
== References == |
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{{reflist |
{{reflist|30em|refs= |
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| refs = |
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<ref name="jpldata">{{cite web |
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|type = 2014-02-12 last obs. |
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|title = JPL Small-Body Database Browser: (2011 MD) |
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|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3568303;cad=1 |
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|publisher = [[Jet Propulsion Laboratory]] |
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|accessdate = 7 February 2018}}</ref> |
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<ref name="MPC-object">{{cite web |
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|title = 2011 MD |
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|work = Minor Planet Center |
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|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=2011+MD |
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|accessdate = 7 February 2018}}</ref> |
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<ref name="MPEC2011-M23">{{Cite web |
<ref name="MPEC2011-M23">{{Cite web |
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|title=MPEC 2011-M23 : 2011 MD |
|title=MPEC 2011-M23 : 2011 MD |
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|publisher=IAU Minor Planet Center |
|publisher=[[IAU Minor Planet Center]] |
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|date=2011-06-23 |
|date=2011-06-23 |
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|url=http://www.minorplanetcenter.net/mpec/K11/K11M23.html |
|url=http://www.minorplanetcenter.net/mpec/K11/K11M23.html |
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|accessdate=2013-01-05}} (K11M00D)</ref> |
|accessdate=2013-01-05}} (K11M00D)</ref> |
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<ref name="NASA-news">{{cite web|author=Don Yeomans |author2=Paul Chodas |name-list-style=amp |url=http://neo.jpl.nasa.gov/news/news172.html |title=Bend it Like Beckham! Small Asteroid to Whip Past Earth on June 27, 2011 |publisher=[[NASA]]/JPL Near-Earth Object Program Office |date=June 23, 2011 |accessdate=June 26, 2011 |archiveurl=https://web.archive.org/web/20110704093604/http://neo.jpl.nasa.gov/news/news172.html |archivedate=4 July 2011 |url-status=dead }}</ref> |
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<ref name="jpldata">{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2011MD;cad=1 |title=JPL Small-Body Database Browser (2011 MD) |author=NASA [[Jet Propulsion Laboratory|JPL]] |accessdate= 2013-01-05 }}</ref> |
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<ref name="NatGeo">{{cite web | url=http://news.nationalgeographic.com/news/2011/06/110627-asteroid-earth-close-pass-weiss-moon-space-science/ | archive-url=https://web.archive.org/web/20110628180228/http://news.nationalgeographic.com/news/2011/06/110627-asteroid-earth-close-pass-weiss-moon-space-science/ | url-status=dead | archive-date=28 June 2011 | title=Asteroid Just Buzzed Earth—Came Closer Than the Moon}}</ref> |
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<ref name="SKY1">{{cite web |work= Sky & Telescope observing blog |url=http://www.skyandtelescope.com/community/skyblog/observingblog/124430479.html |title=Asteroid To Buzz Earth Monday, June 27th | author=Tony Flanders |date=June 23, 2011 |accessdate= June 27, 2011 }}</ref> |
<ref name="SKY1">{{cite web |work= Sky & Telescope observing blog |url=http://www.skyandtelescope.com/community/skyblog/observingblog/124430479.html |title=Asteroid To Buzz Earth Monday, June 27th | author=Tony Flanders |date=June 23, 2011 |accessdate= June 27, 2011 }}</ref> |
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<ref name="MANIA">{{cite web |work= Skymania: Astronomy and space guide |
<ref name="MANIA">{{cite web |work= Skymania: Astronomy and space guide |url= http://www.skymania.com/wp/2011/06/incoming-new-asteroid-will-scrape-past.html |title= Incoming! Another asteroid to skim by |author= Paul Sutherland |date= June 23, 2011 |accessdate= June 26, 2011 |archiveurl= https://web.archive.org/web/20110701112135/http://www.skymania.com/wp/2011/06/incoming-new-asteroid-will-scrape-past.html |archivedate= 1 July 2011 |url-status= dead }}</ref> |
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<ref name="NASA2014-195">{{cite web |url=http://www.jpl.nasa.gov/news/news.php?release=2014-195 |title=NASA Announces Latest Progress in Hunt for Asteroids |author=NASA [[Jet Propulsion Laboratory|JPL]] |accessdate= 2014-06-19 }}</ref> |
<ref name="NASA2014-195">{{cite web |url=http://www.jpl.nasa.gov/news/news.php?release=2014-195 |title=NASA Announces Latest Progress in Hunt for Asteroids |author=NASA [[Jet Propulsion Laboratory|JPL]] |website=[[Jet Propulsion Laboratory]] |accessdate= 2014-06-19 }}</ref> |
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<ref name="Mommert2014">{{cite journal |title=Physical properties of near-earth asteroid 2011 MD |arxiv=1406.5253 |author=Mommert, M. |date= 2014 |journal=Astrophys. J. |volume=789 |issue=1 |page=L22 |display-authors=etal|bibcode = 2014ApJ...789L..22M |doi = 10.1088/2041-8205/789/1/L22 |s2cid=67851874 }}</ref> |
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}} |
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<ref name="AP-20140619">{{cite news |last=Borenstein |first=Seth |title=Rock that whizzed by Earth may be grabbed by NASA |url=http://apnews.excite.com/article/20140619/us-sci-nasa-asteroid-4e7bba0551.html |date=June 19, 2014 |work=[[AP News]] |accessdate=June 20, 2014 }}</ref> |
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==External links== |
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}} <!-- end of reflist --> |
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== External links == |
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{{Commons category|2011 MD}} |
{{Commons category|2011 MD}} |
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*[http://orbit.psi.edu/~tricaric/2011MD.html Encounter animations] (Pasquale Tricarico) |
* [http://orbit.psi.edu/~tricaric/2011MD.html Encounter animations] {{Webarchive|url=https://web.archive.org/web/20180627144706/http://orbit.psi.edu/~tricaric/2011MD.html |date=27 June 2018 }} (Pasquale Tricarico) |
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* {{NeoDys|2011+MD}} |
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* {{ESA-SSA|2011MD}} |
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* {{JPL small body}} |
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<!--use upon numbering: {{Minor planets navigator | |number=? | }} --> |
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{{Small Solar System bodies}} |
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{{2011 in space}} |
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{{Authority control}} |
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{{DEFAULTSORT:2011 MD}} |
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<!--- Categories ---> |
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[[Category: |
[[Category:Apollo asteroids|#]] |
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[[Category: |
[[Category:Amor asteroids|#]] |
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[[Category: |
[[Category:Minor planet object articles (unnumbered)]] |
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[[Category: |
[[Category:Fast rotating minor planets|#]] |
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[[Category:Near-Earth objects in 2011|20110627]] |
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[[Category:Astronomical objects discovered in 2011|20110622]] |
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[[Category:Near-Earth objects in 2024]] |
![]()
2011 MD imaged by Spitzer in February 2014
| |
Discovery[1][2] | |
---|---|
Discovered by | LINEAR |
Discovery site | Lincoln Lab's ETS |
Discovery date | 2011 June 22 (first observed only) |
Designations | |
2011 MD | |
NEO · Apollo[1] · Amor[3] | |
Orbital characteristics[1] | |
Epoch 13 July 2011 (JD 2455755.5) | |
Uncertainty parameter2[1] · 0[3] | |
Observation arc | 2.65 yr (967 days) |
Aphelion | 1.1031 AU |
Perihelion | 1.0161 AU |
1.0596 AU | |
Eccentricity | 0.0411 |
1.09 yr (398 days) | |
11.051° | |
0° 54m 13.32s / day | |
Inclination | 2.5624° |
273.96° | |
4.6748° | |
Earth MOID | 0.0003 AU (0.1 LD) |
Physical characteristics | |
Mean diameter | 6 m (estimate)[4][5] |
Mean density | 1 g/cm3 (est. rubble pile)[4] |
0.1937 h[1] | |
0.3[5] | |
28.0[1] | |
2011 MD is a bright micro-asteroid, classified as near-Earth object of the Apollo and Amor group, respectively.[1][3] On 27 June 2011, at around 17:00 UTC (13:00 EDT), the object passed exceptionally close to Earth's surface at a distance of approximately 12,000 kilometers (7,500 mi), roughly the diameter of the Earth.[6][7][8]
Although 2011 MD was initially believed to be space junk, subsequent observations confirmed that it is an asteroid. A few hours before the asteroid's nearest approach in 2011, it appeared close to the Sun, so observations were possible for only a brief period. Backyard astronomers were able to observe it with telescopes from Australia, southern Africa, and the Americas.[7]
2011 MD was discovered on 22 June 2011, by astronomers of the Lincoln Near-Earth Asteroid Research (LINEAR) at the U.S. Lincoln Laboratory Experimental Test Site in Socorro, New Mexico, by a pair of robotic telescopes. According to original rough estimates, the asteroid's length was between 10 and 45 meters (30 and 150 ft).[3][9] However, according to the more recent absolute magnitude (H) measurement of 28.1[1] and its albedo of 0.3, the asteroid is closer to 6 meters or 20 feet in diameter.[5]
Emily Baldwin of Astronomy Now said that there was no threat of collision, and should the asteroid enter Earth's atmosphere, it would "mostly burn up in a brilliant fireball, possibly scattering a few meteorites", causing no likely harm to life or property on the ground.[9]
The 27 June 2011 close approach to Earth increased the orbital period of 2011 MD from 380 days to 396 days. During close approach the asteroid passed Earth at a relative speed of 6.7 km/s[1] with a geocentric eccentricity of 1.1.
2011 MD was observed by the Spitzer Space Telescope in February 2014 and estimated to be 6 meters (20 ft) in diameter.[4] The asteroid is a porous rubble pile with a density similar to water.[4] On 19 June 2014, NASA reported that asteroid 2011 MD was a prime candidate for capture by the Asteroid Redirect Mission (ARM) in the early 2020s.[10]
Parameter | Epoch | aphelion (Q) |
perihelion (q) |
Semi-major axis (a) |
eccentricity (e) |
Period (p) |
inclination (i) |
Longitude ascending node (Ω) |
Mean anomaly (M) |
Argument of perihelion (ω) |
---|---|---|---|---|---|---|---|---|---|---|
Units | AU | — | (days) | (°) | ||||||
Pre-flyby | 2011-Jun-01 | 1.043 | 1.006 | 1.025 | 0.01804 | 379.1 | 2.739° | 97.79° | 269.8° | 244.3° |
Post-flyby | 2011-Aug-01 | 1.097 | 1.016 | 1.056 | 0.03875 | 396.9 | 2.477° | 273.0° | 29.09° | 4.734° |
2011 in space
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