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2011 XC2

2011 XC2
Discovery[1]
Discovered byLINEAR (704)
Discovery date8 December 2011
Designations
2011 XC2
Apollo Apollo
NEO[2]
Orbital characteristics[2]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 7
Observation arc22 days
Aphelion3.1579 AU (472.42 Gm) (Q)
Perihelion0.83844 AU (125.429 Gm) (q)
1.9982 AU (298.93 Gm) (a)
Eccentricity0.58040 (e)
2.82 yr (1031.7 d)
176.76° (M)
0° 20m 56.184s /day (n)
Inclination28.768° (i)
70.686° (Ω)
306.58° (ω)
Earth MOID0.00132534 AU (198,268 km)
Jupiter MOID2.67756 AU (400.557 Gm)
Physical characteristics
Dimensions~85 meters (279 ft)[3]
60–140 meters[4]
Mass8.4×108 kg (assumed)[3]
23.2[2]

2011 XC2 (also written 2011 XC2) is a near-Earth asteroid roughly 60–140 meters (200–460 ft) in diameter that passed less than 1 lunar distance from Earth on 3 December 2011.[5]

From mid October 2011 until 3 December 2011 15:00 UT the small dim asteroid had an elongation less than 60 degrees from the Sun.[6] (While less than 18 degrees from the Sun any dim asteroid can be lost in astronomical twilight, and many observatories can not see below ~40 degrees from the horizon.) On 3 December 2011 at 15:20 UT the asteroid passed 0.0023 AU (340,000 km; 210,000 mi) from Earth and at 16:20 UT passed 0.0016 AU (240,000 km; 150,000 mi) from the Moon.[5] The asteroid was then discovered on 8 December 2011 by Lincoln Near-Earth Asteroid Research (LINEAR) at an apparent magnitude of 19 using a 1.0-meter (39 in) reflecting telescope.[1] At the time of discovery the asteroid was near opposition to the Sun.[6]

It has an observation arc of 22 days with an uncertainty parameter of 7.[2] Virtual clones of the asteroid that fit the uncertainty region in the known trajectory show a 1 in 455,000 chance that the asteroid will impact Earth on 2 December 2056.[3] With a 2056 Palermo Technical Scale of −4.35,[3] the odds of impact by 2011 XC2 in 2056 are about 22387 times less[7] than the background hazard level of Earth impacts which is defined as the average risk posed by objects of the same size or larger over the years until the date of the potential impact.[8] Using the nominal orbit, JPL Horizons shows that the asteroid will be 3.8 AU (570,000,000 km; 350,000,000 mi) from Earth on 2 December 2056.[9]

References

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  1. ^ a b "MPEC 2011-X35 : 2011 XC2". IAU Minor Planet Center. 11 December 2011. Retrieved 20 February 2014. (K11X02C)
  2. ^ a b c d "JPL Small-Body Database Browser: (2011 XC2)" (last observation: 2011-12-30; arc: 22 days). Jet Propulsion Laboratory. Archived from the original on 28 May 2019. Retrieved 1 April 2016.
  3. ^ a b c d "Earth Impact Risk Summary: 2011 XC2". NASA/JPL Near-Earth Object Program Office. Retrieved 20 February 2014.
  4. ^ "Absolute Magnitude (H)". NASA/JPL. Archived from the original on 2 March 2001. Retrieved 20 February 2014.
  5. ^ a b "JPL Close-Approach Data: (2011 XC2)" (last observation: 2011-12-30; arc: 22 days). Retrieved 20 February 2014.
  6. ^ a b "2011XC2 Ephemerides for 11 October 2011 through 17 December 2011". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 20 February 2014.
  7. ^ Math: 104.35 = 22387
  8. ^ "The Palermo Technical Impact Hazard Scale". NASA/JPL Near-Earth Object Program Office. 31 August 2005. Archived from the original on 21 March 2002. Retrieved 20 February 2014.
  9. ^ Horizons output. "Horizon Online Ephemeris System". Retrieved 20 February 2014. (Geocentric Solution)
[edit]
Preceded by Large NEO Earth close approach
(inside the orbit of the Moon)
3 December 2011 		Succeeded by
367943 Duende (2012 DA14)