1994 WR12

1994 WR12 is a sub-kilometer asteroid and near-Earth object of the Aten group, approximately 130 meters (430 feet) in diameter.[3][4] First imaged at Kitami Observatory on 26 November 1994,[1] it was discovered two nights later by American astronomer Carolyn S. Shoemaker at Palomar Observatory on 28 November 1994.[2] The asteroid then went unobserved from 1994 until it was recovered by Mauna Kea in March 2016.[1] It was removed from the Sentry Risk Table on 2 April 2016.[5]

1994 WR12
Discovery [1][2]
Discovered byC. S. Shoemaker
Discovery sitePalomar Obs.
Discovery date28 November 1994
Designations
1994 WR12
NEO · Aten [1][3]
Orbital characteristics [3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc25.03 yr (9,141 d)
Aphelion1.0578 AU
Perihelion0.4565 AU
0.7571 AU
Eccentricity0.3971
241 days
39.352°
1° 29m 45.96s / day
Inclination6.8587°
62.687°
206.07°
Earth MOID0.0018 AU (0.701 LD)
Physical characteristics
Mean diameter
130 m (est.)[4]
Mass2.9×109 kg (est.)[4]
22.3[3]

    Description

    1994 WR12 orbits the Sun at a distance of 0.5–1.1 AU once every 8 months (240 days). Its orbit has an eccentricity of 0.40 and an inclination of 7° with respect to the ecliptic.[3]

    It has an Earth minimum orbital intersection distance of 0.0019 AU (284,000 km), which translates into 0.7 lunar distances.[3] On 25 November 2046, it will pass 0.0108589 AU (1,624,470 km) from Earth with an uncertainty of ±800 km.[6] While listed on the Sentry Risk Table the range for the 2046 close approach distance varied from 0.001 AU (150,000 km) to 0.039 AU (5,800,000 km) from Earth.[6]

    While listed on the Sentry Risk Table,[7] virtual clones of the asteroid that fit the uncertainty in the known trajectory showed 116 potential impacts between 2054 and 2109.[4] It had about a cumulative 1 in 9090 chance of impacting the Earth.[4] The formerly poorly known trajectory of this asteroid was further complicated by close approaches to Venus and Mercury.[6] It was recovered by Mauna Kea in March 2016,[1] which extended the observation arc from 34 days to 21 years.

    It is estimated that an impact would produce the equivalent of 77 megatons of TNT,[4] roughly 1.5 times that of most powerful nuclear weapon ever detonated (Tsar Bomba).

    See also

    References
    1. "1994 WR12". Minor Planet Center. Retrieved 30 June 2020.
    2. "MPEC 1994-Y05 : 1994 WR12". IAU Minor Planet Center. 21 December 1994. Retrieved 17 October 2011. (J94W12R)
    3. "JPL Small-Body Database Browser: (1994 WR12)" (2019-12-06 last obs.). Jet Propulsion Laboratory. Retrieved 30 June 2020.
    4. "Archive: Earth Impact Risk Summary: 1994 WR12". NASA/JPL Near-Earth Object Program Office. 26 March 2016. Archived from the original on 26 March 2016.
    5. "Removed Objects". NASA/JPL Near-Earth Object Program Office.
    6. "JPL Close-Approach Data: (1994 WR12)". Retrieved 7 April 2011.
      "(1994 WR12)". Archived from the original on 13 December 2012. Retrieved 29 January 2018. (last observation: 1994-12-31; arc: 35 days; Uncertainty: 8)
    7. "Archive: Sentry Risk Table". NASA/JPL Near-Earth Object Program Office. 29 May 2013. Archived from the original on 29 May 2013.
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