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2006 RH120

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2006 RH120
Discovery[1]
Discovered byCatalina Sky Survey(Eric Christensen)
Discovery date14 September 2006
Designations
2006 RH120
Orbital characteristics[5]
Epoch27 April 2019 (JD2458600.5)
Uncertainty parameter1
Observation arc281 days
Aphelion1.058AU(158.3Gm) (Q)
Perihelion1.0078 AU (150.76 Gm) (q)
1.0331 AU (154.55 Gm) (a)
Eccentricity0.02452 (e)
(Geocentrichyperbolice=2500000)[6]
1.05yr
313.7°(M)
Inclination0.59486° (i)
51.18° (Ω)
~2028-Nov-11
10.060° (ω)
EarthMOID0.01682 AU (2,516,000 km)
JupiterMOID3.93 AU (588 Gm)
Physical characteristics
Dimensions~2–3m[7]
0.1?[clarification needed]
30+ (until 2027)
29.5[9]

2006 RH120is a tinynear-Earth asteroid[9]andfast rotatorwith a diameter of approximately 2–3 meters[7]that ordinarily orbits the Sun but makes close approaches to the Earth–Moon system around every twenty years,[10]when it can temporarily enterEarthorbit throughtemporary satellitecapture (TSC). Most recently, it was in Earth orbit from July 2006 to July 2007,[11]during which time it was never more than 0.0116AU(1.74 millionkm) from Earth.[12]As a consequence of its temporary orbit around the Earth, it is currently the second smallest asteroid in the Solar System with a well-known orbit, after2021 GM1.Until given aminor planet designationon 18 February 2008,[1]the object was known as6R10DB9,an internal identification number assigned by theCatalina Sky Survey.[8]

Discovery

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2006 RH120was discovered on 14 September 2006 by Eric Christensen with the 27-inch (690 mm) Schmidt camera of the Catalina Sky Survey inArizona.[13]"6R10DB9"[13]was the Catalina Sky Survey's own discovery designation for this object, which usually would only be used on theMPC'sNear-Earth Object Confirmation Page(NEOCP) until anIAUdesignation was applied, if the object was classified as a minor object. It was added on 14 September to the NEOCP and subsequently removed with the explanation that it "was not aminor planet".[14]Preliminary orbital calculations indicated it was captured by Earth'sgravityfrom solar orbit of a period of about 12 months,[11]which is similar to that of many spent rocket boosters dating to theApollo programof the 1960s and early 1970s. 6R10DB was assigned the designation2006 RH120on 18 February 2008.[1]

Origin

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Some controversy existed regarding the origin of the object. Upon discovery, it was not given a formal name because its spectrum was consistent with the white titanium-oxide paint used on Saturn V rockets,[15]which meant it could be an artificial object. Precedents for this exist:J002E3is currently thought to be the third-stage SaturnS-IVBbooster fromApollo 12and was in an almost identical orbit,[16]and6Q0B44E,discovered a month earlier, was also thought to be artificial.[17]Its status as a satellite was also debated, with A. W. Harris of theSpace Science Institutecommenting, "Claiming some bit of fluff in a temporary looping orbit to be a 'satellite', with all the baggage that term carries, is mere hype".[10][18]Radarobservations strongly suggest that the object is a natural body.[11]

Orbit

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Analysis has shown thatsolar-radiation pressureisperturbingits motion perceptibly.[19]However, Paul Chodas inJPL's Solar System Dynamics Group suspects that the perturbations are consistent with expectations for a rocky object but not with old flight hardware.[19]One hypothesis is that the object is a piece of lunar rock ejected by an impact.[10]

2006 RH120made four Earth orbits of about three months each withperigee(closest approach to Earth) on 11 September 2006, 3 January 2007, 25 March 2007, and 14 June 2007.[9]During the 12-month capture from July 2006 to July 2007 when it was inside of Earth'shill sphere,[11]it stayed within 0.0116AU(1.74 millionkm) of Earth.[12]It was ejected after the 14 June 2007 perigee when it dipped inside the Moon's orbit to a distance of 276,840 kilometres (172,020 mi).[8]2006 RH120became anApollo-class asteroidin June 2007 as it was escaping Earth's hill sphere. Though it was outside of Earth's hill sphere, the geocentricorbital eccentricitywas not greater than 1 until 17 September 2007.[20]

It is now in solar orbit[18]as anAmor-class asteroid[5]with an orbit completely outside of Earth's orbit. As of 2022, this object is 1.7AUfrom Earth on the other side of the Sun and will not be less than 1 AU from Earth until March 2025.[21]

Future events

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Around 18 August 2028 (±3 days) it will pass Earth with a relative velocity of 136 m/s (300 mph)[9][22]and will then pass Earth with a relative velocity of 784 m/s (1,750 mph) around 9 October 2028 as it speeds up for a November 2028 perihelion passage[23](closest approach to the Sun and when an object moves fastest in its orbit). For comparison, on 13 April 2029, asteroid99942 Apophiswill pass Earth at a relative speed of 7.4 km/s (17,000 mph).[24]

2006 RH120 has a 1-in-200 (0.5%) chance of Earth impact on 8 February 2044 and would impact with a harmless 1 kiloton of energy if it did impact.[25](TheChelyabinsk meteorreleased about 440 kt of energy.)JPL Horizon's nominal orbit has the asteroid passing 0.009AU(1.3 millionkm) from Earth on 9 January 2044 (30 days before the virtual impactor).[26]As a result of a 281 dayobservation arcandradar observations,JPL's solution accounts for non-gravitational forces[9]as the multi-decade motion of a very small object is greatly affected bysolar heating.

2044 Virtual impactor[25]
Date Impact
probability
(1 in) 		JPL Horizons
nominalgeocentric
distance (AU) 		NEODyS
nominal geocentric
distance (AU) 		MPC[27]
nominal geocentric
distance (AU) 		Find_Orb
nominal geocentric
distance (AU) 		uncertainty
region
(3-sigma)
2044-02-08 09:07 200 0.014AU(2.1 millionkm)[28] 0.223 AU (33.4 million km)[29] 0.10 AU (15 million km) 0.23 AU (34 million km)[30] ± 130 million km[28]
Orbit of2006 RH120during a temporary-satellite-capture event
Animation of 2006 RH120 orbit
Around Earth from April 2006 to November 2007
Around Earth from 1978 to 2020
Around Sun from 1600 to 2500
Sun·Earth·Moon·2006 RH120

14 June 2007 perigee

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On 14 June 2007,2006 RH120made its fourth and last perigee of the most recent Earth encounter.[9]It was 0.72lunar distancesat closest, with anapparent magnitudeof 18.5–19.0.AstronomersatJPLGoldstonein California maderadarastrometrymeasurements on 12, 14 and 17 June 2007.

2006 RH120is listed as part of the Near-Earth Object Human Space Flight Accessible Targets Study (NHATS).[31]

See also

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References

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  1. ^abcWilliams, Gareth V (18 February 2008)."MPEC 2008-D12: 2006 RH120".IAU Minor Planet Center.Harvard–Smithsonian Center for Astrophysics.Archivedfrom the original on 9 April 2010.Retrieved26 February2010.
  2. ^WayBack:MPC Epoch 2013 = Amor
  3. ^archive.ph:JPL Epoch 2012 = Apollo
  4. ^archive.ph:Epoch Jan 2007 = Aten with a=0.99au
  5. ^ab"2006 RH120 Orbit".Minor Planet Center.Archivedfrom the original on 25 February 2014.Retrieved7 February2017.
  6. ^"JPL Horizons On-Line Ephemeris for 2006 RH120 orbit of Earth (geocentric) at epoch 2019-Apr-27".JPL Horizons On-Line Ephemeris System.Jet Propulsion Laboratory.Retrieved13 June2022.Geocentric solution. Ephemeris Type: Orbital Elements / Center: @399 / Time Span: 2019-04-27 (to match infobox epoch)
  7. ^abBrent W. Barbee."Accessible Near-Earth Objects (NEOs)"(PDF).12th Meeting of the Small Bodies Assessment Group (SBAG) 2015.Retrieved12 January2015.(pg 17 for diameter)
  8. ^abcGreat Shefford Observatory."2006 RH120 ( = 6R10DB9) – A second moon for the Earth?".Archived fromthe originalon 9 May 2008.Retrieved16 April2008.
  9. ^abcdefg"JPL Small-Body Database Browser: (2006 RH120)"(last observation: 2007-06-22;arc:281 days).Archivedfrom the original on 27 February 2014.Retrieved30 March2016.
  10. ^abcBill Gray.""Pseudo-MPEC" for 6R10DB9 ".Archivedfrom the original on 27 September 2007.Retrieved16 August2007.
  11. ^abcdKwiatkowski, T.; Kryszczyńska, A.; Polińska, M.; Buckley, D. A. H.; O'Donoghue, D.; Charles, P. A.; Crause, L.; Crawford, S.; Hashimoto, Y.; Kniazev, A. (2009)."Photometry of 2006 RH120: an asteroid temporary captured into a geocentric orbit".Astronomy & Astrophysics.495(3): 967–974.Bibcode:2009A&A...495..967K.doi:10.1051/0004-6361:200810965.ISSN0004-6361.
  12. ^ab"Horizons Batch for July 2006 – July 2007 Geocentric distance"(Maximum Apogee occurs 2006-Nov-03 18:54 @ 0.011654 AU).JPL Horizons.Archivedfrom the original on 9 July 2022.Retrieved7 July2022.(JPL#51/Soln.date: 2021-Apr-14) (NEODyS-2 for 3 Nov 2006)
  13. ^ab"Distant Artificial Satellites Observation (DASO) Circular No. 68, 2006 Sept. 17, 16:59 UT".Retrieved26 June2007.
  14. ^"Major News About Minor Objects, April 18, 2007".Archived fromthe originalon 27 November 2012.Retrieved27 June2007.
  15. ^Spectrum measured by Carl Hergenrother and Rob Whitely of the University of Arizona.
  16. ^Yeomans, Don (April 2010). "Is Another Moon Possible?".Astronomy.
  17. ^The Guardian,Spacewatch, 6 September 2006
  18. ^abRoger W. Sinnott (17 April 2007)."Earth's" Other Moon "".Sky & Telescope.Archivedfrom the original on 2 April 2012.Retrieved25 February2010.
  19. ^abDr. Lance A. M. Benner (20 June 2007)."6R10DB9 Planning".JPL/NASA Asteroid Radar Research.Retrieved27 February2010.
  20. ^"JPL Horizons On-Line Ephemeris for 2006 RH120 orbit of Earth (geocentric) at epoch 2007-Sep-17".JPL Horizons On-Line Ephemeris System.Jet Propulsion Laboratory.Retrieved12 July2022.Geocentric solution. Ephemeris Type: Orbital Elements / Center: @399
  21. ^"2006RH120 Ephemerides for 2007 to 2028".NEODyS(Near Earth Objects – Dynamic Site).Retrieved24 February2015.
  22. ^"2006 RH120".Space Reference.Retrieved12 June2022.
  23. ^"Horizons Batch for 2028 approaches".JPL Horizons.Retrieved13 June2022.
  24. ^"JPL Close-Approach Data: 99942 Apophis (2004 MN4)".Retrieved15 February2015.
  25. ^ab"Earth Impact Risk Summary: 2006 RH120".NASA/JPL Near-Earth Object Program Office.Archivedfrom the original on 13 June 2022.Retrieved13 June2022.
  26. ^"Horizons Batch for Jan 2044 – Feb 2044 Geocentric distance"(Earth approach occurs 2044-Jan-29 12:34 @ 0.006885 AU).JPL Horizons.Retrieved10 July2022.(JPL#51/Soln.date: 2021-Apr-14)
  27. ^"MPC Ephemeris Service".IAUMinor Planet Center.Retrieved7 July2022.
  28. ^ab"Horizons Batch for 2044-02-08 09:07 Virtual Impactor".JPL Horizons.Archivedfrom the original on 7 July 2022.Retrieved7 July2022.RNG_3sigma = uncertainty range in km. (JPL#51/Soln.date: 2021-Apr-14 generates RNG_3sigma =78335191kmfor 2044-Feb-08 09:07.)
  29. ^"2006RH120 Ephemerides for 8 February 2044".NEODyS (Near Earth Objects – Dynamic Site).Archivedfrom the original on 7 July 2022.Retrieved7 July2022.
  30. ^"Find_Orb for 2044-02-08".Project Pluto.Archivedfrom the original on 7 July 2022.Retrieved7 July2022.
  31. ^"NHATS Object/Trajectory Details: (2006 RH120)".Archived fromthe originalon 24 February 2015.Retrieved24 February2015.
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