(276033) 2002 AJ129
The orbit is highly elliptical, moving outside Mars and inside Mercury. Positions shown for 31 January 2018 before flyby.
Discovery[1][2]
Discovered byNEAT
Discovery siteHaleakala Obs.
Discovery date15 January 2002
Designations
(276033) 2002 AJ129
2002 AJ129
Orbital characteristics[3][4]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc14.23 yr (5,199 days)
Aphelion2.6254 AU
Perihelion0.1167 AU
1.3711 AU
Eccentricity0.9149
1.61 yr (586 days)
288.23°
0° 36m 50.04s / day
Inclination15.449°
138.05°
211.01°
Earth MOID0.0060 AU (2.3 LD)
Physical characteristics
Mean diameter
0.5–1.2 km[5]
18.7[3]

(276033) 2002 AJ129, provisional designation 2002 AJ129, is a Mercury-crossing asteroid. It has the ninth-smallest perihelion of all numbered asteroids, after asteroids such as 2000 BD19, 2004 UL, and 2008 XM.[6] It makes close approaches to all of the inner planets[3] and asteroid 4 Vesta.[7] The asteroid is estimated to be between 0.5–1.2 kilometers (0.3–0.7 mi) across.[5] In January 2018 there was much media hype about this asteroid being classified as a potentially hazardous asteroid, although there is no known threat of an impact for hundreds if not thousands of years. The media has compared the size of the asteroid to the Burj Khalifa in Dubai.[8]

Description

2002 AJ129 was discovered on 15 January 2002 by astronomers of the NEAT team at Haleakala Observatory, Hawaii, United States.[1][2] It was removed from the Sentry Risk Table on 3 February 2002.[9]

It is a Mercury-, Venus-, Earth- and Mars-crossing asteroid. With an observation arc of 14 years, it has a well determined orbit and was last observed in 2016.[3] It is classified as an Apollo asteroid[3] because it is a near-Earth asteroid with a semi-major axis larger than Earth's. It is also categorized as a potentially hazardous asteroid,[3] but that does not mean there is a near-term threat of an impact. It is a potentially hazardous asteroid merely as a result of its size (absolute magnitude H ≤ 22) and Earth minimum orbit intersection distance (Earth MOID ≤ 0.05 AU).

2018 approach

On 4 February 2018 at 21:31 UT, the asteroid passed about 0.028126 AU (4,207,600 km; 2,614,500 mi) from Earth.[3][10] The 2018 Earth approach distance was known with a 3-sigma accuracy of ±200 km.[3] Goldstone is scheduled to observe the asteroid from 3 to 6 February.[11] By 4 February 2018 11:00 UT, the asteroid brightened to apparent magnitude 14 and had a solar elongation of more than 100°.[12]

2172 approach

On 8 February 2172, the asteroid will pass about 0.00458 AU (685,000 km; 426,000 mi) from Earth.[3] The 2172 Earth approach distance is known with a 3-sigma accuracy of ±4000 km.

As we look even further into the future the known trajectory becomes more divergent. By the Earth approach of 0.24 AU (36,000,000 km; 22,000,000 mi) on 19 February 2196 the uncertainty increases to ±2.4 million km.[3]

History of close approaches of large near-Earth objects since 1908 (A)
PHA Date Approach distance in lunar distances Abs. mag
(H) 		Diameter (C)
(m) 		Ref (D)
Nominal(B) Minimum Maximum
(152680) 1998 KJ9 1914-12-31 0.606 0.604 0.608 19.4 279–900 data
(458732) 2011 MD5 1918-09-17 0.911 0.909 0.913 17.9 556–1795 data
(163132) 2002 CU11 1925-08-30 0.903 0.901 0.905 18.5 443–477 data
69230 Hermes 1937-10-30 1.926 1.926 1.927 17.5 700-900[13] data
69230 Hermes 1942-04-26 1.651 1.651 1.651 17.5 700-900[13] data
2017 NM6 1959-07-12 1.89 1.846 1.934 18.8 580–1300 data
(27002) 1998 DV9 1975-01-31 1.762 1.761 1.762 18.1 507–1637 data
2002 NY40 2002-08-18 1.371 1.371 1.371 19.0 335–1082 data
2004 XP14 2006-07-03 1.125 1.125 1.125 19.3 292–942 data
2015 TB145 2015-10-31 1.266 1.266 1.266 20.0 620-690 data
(137108) 1999 AN10 2027-08-07 1.014 1.010 1.019 17.9 556–1793 data
(153814) 2001 WN5 2028-06-26 0.647 0.647 0.647 18.2 921–943 data
99942 Apophis 2029-04-13 0.0981 0.0963 0.1000 19.7 310–340 data
2017 MB1 2072-07-26 1.216 1.215 2.759 18.8 367–1186 data
2011 SM68 2072-10-17 1.875 1.865 1.886 19.6 254–820 data
(163132) 2002 CU11 2080-08-31 1.655 1.654 1.656 18.5 443–477 data
(416801) 1998 MZ 2116-11-26 1.068 1.068 1.069 19.2 305–986 data
(153201) 2000 WO107 2140-12-01 0.634 0.631 0.637 19.3 427–593 data
(276033) 2002 AJ129 2172-02-08 1.783 1.775 1.792 18.7 385–1242 data
(290772) 2005 VC 2198-05-05 1.951 1.791 2.134 17.6 638–2061 data
(A) This list includes near-Earth approaches of less than 2 lunar distances (LD) of objects with H brighter than 20.
(B) Nominal geocentric distance from the center of Earth to the center of the object (Earth has a radius of approximately 6,400 km).
(C) Diameter: estimated, theoretical mean-diameter based on H and albedo range between X and Y.
(D) Reference: data source from the JPL SBDB, with AU converted into LD (1 AU≈390 LD)
(E) Color codes:   unobserved at close approach   observed during close approach   upcoming approaches

References

  1. ^ a b "MPEC 2002-B14 : 2002 AJ129". IAU Minor Planet Center. 19 January 2002. Retrieved 19 January 2018. (K02AC9J)
  2. ^ a b c "276033 (2002 AJ129)". Minor Planet Center. Retrieved 8 February 2018.
  3. ^ a b c d e f g h i j k "JPL Small-Body Database Browser: 276033 (2002 AJ129)" (2016-04-10 last obs.). Jet Propulsion Laboratory. Archived from the original on 18 January 2018. Retrieved 8 February 2018.
  4. ^ AstDys-2 Retrieved 2011 September 13
  5. ^ a b NeoDys-2 Retrieved 2011 September 13
  6. ^ List of asteroids with q<0.3075 AU generated by the JPL Small-Body Database Search Engine Retrieved 2011 September 10
  7. ^ NEODyS-2 Close approaches
  8. ^ "A 'potentially hazardous' asteroid bigger than Burj Khalifa is about to fly near our planet". Business Insider. Retrieved 19 January 2018.
  9. ^ "NEOs Removed from Impact Risks Tables". Archived from the original on 2 June 2002.
  10. ^ "Asteroid 2002 AJ129 to Fly Safely Past Earth February 4 [2018]". NASA/Jet Propulsion Laboratory. 19 January 2018. Retrieved 8 February 2018.
  11. ^ Dr. Lance A. M. Benner (1 February 2018). "Goldstone Radar Observations Planning: Asteroids 2002 AJ129, 2014 SR339, and 2015 BN509". NASA/JPL Asteroid Radar Research. Retrieved 3 February 2018.
  12. ^ "(276033) 2002AJ129 Ephemerides for February 2018". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 3 February 2018.
  13. ^ a b Marchis, F.; et al. "Multiple asteroid systems: Dimensions and thermal properties from Spitzer Space Telescope and ground-based observations". Icarus. 221 (2): 1130–1161. Bibcode:2012Icar..221.1130M. doi:10.1016/j.icarus.2012.09.013. Retrieved 24 August 2018.

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