2006 RH120
Discovery[1] | |
---|---|
Discovered by | Catalina Sky Survey(Eric Christensen) |
Discovery date | 14 September 2006 |
Designations | |
2006 RH120 | |
Orbital characteristics[5] | |
Epoch27 April 2019 (JD2458600.5) | |
Uncertainty parameter1 | |
Observation arc | 281 days |
Aphelion | 1.058AU(158.3Gm) (Q) |
Perihelion | 1.0078 AU (150.76 Gm) (q) |
1.0331 AU (154.55 Gm) (a) | |
Eccentricity | 0.02452 (e) (Geocentrichyperbolice=2500000)[6] |
1.05yr | |
313.7°(M) | |
Inclination | 0.59486° (i) |
51.18° (Ω) | |
~2028-Nov-11 | |
10.060° (ω) | |
EarthMOID | 0.01682 AU (2,516,000 km) |
JupiterMOID | 3.93 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
[edit]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
[edit]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
[edit]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
[edit]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.
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] |
![](https://upload.wikimedia.org/wikipedia/commons/thumb/9/9b/Orbit_of_2006_RH120.png/220px-Orbit_of_2006_RH120.png)
14 June 2007 perigee
[edit]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
[edit]- 1991 VG– temporaryEarthsatellite discovered in 1991
- 2020 CD3– another temporary Earthsatellitediscovered in 2020
- 2023 FY3– another temporary Earth satellite discovered in 2023
- 6Q0B44E– small Earth satellite, probably artificial
- 3753 Cruithne–horseshoecompanion of the Earth
- 2002 AA29– horseshoe companion of the Earth
- (419624) 2010 SO16– horseshoe companion of the Earth
- Natural satellite
- Claimed moons of Earth
- Quasi-satellite
- Space debris
References
[edit]- ^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.
- ^WayBack:MPC Epoch 2013 = Amor
- ^archive.ph:JPL Epoch 2012 = Apollo
- ^archive.ph:Epoch Jan 2007 = Aten with a=0.99au
- ^ab"2006 RH120 Orbit".Minor Planet Center.Archivedfrom the original on 25 February 2014.Retrieved7 February2017.
- ^"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)
- ^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)
- ^abcGreat Shefford Observatory."2006 RH120 ( = 6R10DB9) – A second moon for the Earth?".Archived fromthe originalon 9 May 2008.Retrieved16 April2008.
- ^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.
- ^abcBill Gray.""Pseudo-MPEC" for 6R10DB9 ".Archivedfrom the original on 27 September 2007.Retrieved16 August2007.
- ^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.
- ^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)
- ^ab"Distant Artificial Satellites Observation (DASO) Circular No. 68, 2006 Sept. 17, 16:59 UT".Retrieved26 June2007.
- ^"Major News About Minor Objects, April 18, 2007".Archived fromthe originalon 27 November 2012.Retrieved27 June2007.
- ^Spectrum measured by Carl Hergenrother and Rob Whitely of the University of Arizona.
- ^Yeomans, Don (April 2010). "Is Another Moon Possible?".Astronomy.
- ^The Guardian,Spacewatch, 6 September 2006
- ^abRoger W. Sinnott (17 April 2007)."Earth's" Other Moon "".Sky & Telescope.Archivedfrom the original on 2 April 2012.Retrieved25 February2010.
- ^abDr. Lance A. M. Benner (20 June 2007)."6R10DB9 Planning".JPL/NASA Asteroid Radar Research.Retrieved27 February2010.
- ^"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
- ^"2006RH120 Ephemerides for 2007 to 2028".NEODyS(Near Earth Objects – Dynamic Site).Retrieved24 February2015.
- ^"2006 RH120".Space Reference.Retrieved12 June2022.
- ^"Horizons Batch for 2028 approaches".JPL Horizons.Retrieved13 June2022.
- ^"JPL Close-Approach Data: 99942 Apophis (2004 MN4)".Retrieved15 February2015.
- ^ab"Earth Impact Risk Summary: 2006 RH120".NASA/JPL Near-Earth Object Program Office.Archivedfrom the original on 13 June 2022.Retrieved13 June2022.
- ^"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)
- ^"MPC Ephemeris Service".IAUMinor Planet Center.Retrieved7 July2022.
- ^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.)
- ^"2006RH120 Ephemerides for 8 February 2044".NEODyS (Near Earth Objects – Dynamic Site).Archivedfrom the original on 7 July 2022.Retrieved7 July2022.
- ^"Find_Orb for 2044-02-08".Project Pluto.Archivedfrom the original on 7 July 2022.Retrieved7 July2022.
- ^"NHATS Object/Trajectory Details: (2006 RH120)".Archived fromthe originalon 24 February 2015.Retrieved24 February2015.
External links
[edit]- Great Shefford Observatory's 6R10DB9 images and background
- Earth's "Other Moon",Roger W. Sinnott,Sky & Telescope,17 April 2007
- JPL Radar Astrometry Page
- Bill Gray's Pseudo-MPEC Page on 6R10DB9
- Photometry of 2006 RH120: an asteroid temporarily captured into a geocentric orbit (Astronomy & Astrophysics 2009)
- Interactive 3D visualisation of the Earth 2006 RH120 capture event
- 2006 RH120atNeoDyS-2, Near Earth Objects—Dynamic Site
- 2006 RH120atESA–space situational awareness
- 2006 RH120at theJPL Small-Body Database