2011 MD

{{Short description|Asteroid in the solar system}}

{{Use dmy dates|date=February 2018}}

{{Infobox planet

| minorplanet = yes

| name = 2011 MD

| background = #FFC2E0

| image = PIA18453-Asteroid2011MD-SpitzerSpaceTelescope-IRAC-Feb2014.jpg

| image_scale =

| caption = {{mp|2011 MD}} imaged by Spitzer in February 2014

| discovery_ref =

| discoverer = LINEAR

| discovery_site = Lincoln Lab's ETS

| discovered = 2011 June 22
{{small|(first observed only)}}

| mpc_name = 2011 MD

| alt_names =

| pronounced =

| named_after =

| mp_category = {{nowrap|NEO{{·}}Apollo{{·}}Amor}}

| orbit_ref =

| epoch = 13 July 2011 (JD 2455755.5)

| uncertainty = 2{{·}}0

| observation_arc = 2.65 yr (967 days)

| aphelion = 1.1031 AU

| perihelion = 1.0161 AU

| semimajor = 1.0596 AU

| eccentricity = 0.0411

| period = 1.09 yr (398 days)

| mean_anomaly = 11.051°

| mean_motion = {{Deg2DMS|0.9037|sup=ms}} / day

| inclination = 2.5624°

| asc_node = 273.96°

| arg_peri = 4.6748°

| moid = 0.0003 AU (0.1 LD)

| mean_diameter = {{val|6|ul=m}} {{small|(estimate)}}

| density = {{val|1|ul=g/cm3}} {{small|(est. rubble pile)}}

| albedo = 0.3

| rotation = {{val|0.1937|ul=h}}

| abs_magnitude = 28.0

}}

2011 MD is a bright micro-asteroid, classified as near-Earth object of the Apollo and Amor group, respectively. 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.

Description

File:2011 MD on Jun 26.jpg

Although {{mp|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.

{{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 in Socorro, 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}}. However, according to the more recent absolute magnitude (H) measurement of 28.1 and its albedo of 0.3, the asteroid is closer to 6 meters or 20 feet in diameter.

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.

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 with a geocentric eccentricity of 1.1.

{{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. The asteroid is a porous rubble pile with a density similar to water. On 19 June 2014, NASA reported that asteroid {{mp|2011 MD}} was a prime candidate for capture by the Asteroid Redirect Mission (ARM) in the early 2020s.

class=wikitable style="font-size: 0.9em;"
valign=top

!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)

valign=top

! Units

!

!colspan=3|AU

! —

! (days)

!colspan=4| (°)

align=center

!Pre-flyby

| 2011-Jun-01

| 1.043

| 1.006

| 1.025

| 0.01804

| 379.1

| 2.739°

| 97.79°

| 269.8°

| 244.3°

align=center

! Post-flyby

| 2011-Aug-01

| 1.097

| 1.016

| 1.056

| 0.03875

| 396.9

| 2.477°

| 273.0°

| 29.09°

| 4.734°

= Gallery =

{{multiple image

| header =

| align = left

| direction = horizontal

| total_width = 900

| image1 = Trajectory of near-Earth asteroid 2011 MD 1.gif

| width1 =

| alt1 =

| caption1 = Trajectory of {{mp|2011 MD}} projected onto the Earth's orbital plane. Note, from this viewing angle, the asteroid passes underneath the Earth.

| image2 = Trajectory of near-Earth asteroid 2011 MD 2.gif

| width2 =

| alt2 =

| caption2 = Trajectory of {{mp|2011 MD}} from the general direction of the Sun.

| footer =

| image3 = Spacious Structure of Asteroid 2011 MD (Artist's Concept).jpg

| width3 =

| alt3 =

| caption3 = Artist's concept of spacious structure of asteroid 2011 MD{{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}}

}}

{{clear|left}}

See also

References

{{reflist|30em|refs=

{{cite web

|type = 2014-02-12 last obs.

|title = JPL Small-Body Database Browser: (2011 MD)

|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3568303;cad=1

|publisher = Jet Propulsion Laboratory

|accessdate = 7 February 2018}}

{{cite web

|title = 2011 MD

|work = Minor Planet Center

|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=2011+MD

|accessdate = 7 February 2018}}

{{Cite web

|title=MPEC 2011-M23 : 2011 MD

|publisher=IAU Minor Planet Center

|date=2011-06-23

|url=http://www.minorplanetcenter.net/mpec/K11/K11M23.html

|accessdate=2013-01-05}} (K11M00D)

{{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 }}

{{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}}

{{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 }}

{{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 }}

{{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 JPL |website=Jet Propulsion Laboratory |accessdate= 2014-06-19 }}

{{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 }}

{{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 }}

}}