1994 WR12

1994 WR₁₂

Discovery[1][2]
Discovered by	C. S. Shoemaker
Discovery site	Palomar Obs.
Discovery date	28 November 1994
Designations
MPC designation	1994 WR12
Minor planet category	NEO · Aten[1][3]
Orbital characteristics[3]
Epoch 2022-Jan-21 (JD 2459600.5)
Uncertainty parameter 0
Observation arc	27.01 yr (9,864 d)
Aphelion	1.0577 AU (158.23 million km)
Perihelion	0.4562 AU (68.25 million km)
Semi-major axis	0.7570 AU (113.25 million km)
Eccentricity	0.39735
Orbital period (sidereal)	240.6 days (0.659 yr)
Mean anomaly	217.06°
Mean motion	1° 29^m 45.96^s / day
Inclination	6.8515°
Longitude of ascending node	62.608°
Argument of perihelion	206.03°
Earth MOID	0.0018 AU (0.70 LD)
Physical characteristics
Mean diameter	130 m (est.)[4] 92 – 210 m (CNEOS)
Mass	2.9×10^9 kg (est.)[4]
Absolute magnitude (H)	22.3[3]

1994 WR₁₂ is an asteroid and near-Earth object approximately 130 meters (430 feet) in diameter.^[3][4] As a member of the Aten group almost all of its orbit is closer to the Sun than Earth is. On 24 November 1994 it passed about 374100 km from the Moon.^[3] 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]

Close approaches^[3]

Date	JPL SBDB nominal geocentric distance	uncertainty region (3-sigma)
2021-11-29	6152189 km	± 34 km[6]
2046-11-25	1633719 km	± 4133 km
2190-11-23	135000000 km	± 815 million km[7]

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 0.0018 AU (269,000 km), which translates into 0.7 lunar distances.^[3] On 25 November 2046, it will pass 1633719 km from Earth with an uncertainty of ±4133 km.^[3] 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.^[8]

While listed on the Sentry Risk Table,^[9] 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.^[3] 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).

It has too a unique characteristic: it's complanar with Mercury, it can to be a fragment thrown away by an asteroid impact on Mercury, it's very little MOID with the Earth can produce a meteor shower on Earth and if the meteoroids were large enough even Mercurian meteorites.

See also

• Lost asteroids

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)" (2022-01-25 last obs.). Jet Propulsion Laboratory. Archived from the original on 30 November 2017. Retrieved 29 November 2021.
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. "Horizons Batch for 2021-Nov-29 06:05 UT". JPL Horizons. Archived from the original on 19 November 2021. Retrieved 28 November 2021.
7. "Horizons Batch for 2190-Nov-23 22:27 UT". JPL Horizons. Archived from the original on 20 November 2021. Retrieved 29 November 2021.
8. "JPL Close-Approach Data: (1994 WR12)". Retrieved 29 November 2021.
   "(1994 WR12)". Archived from the original on 13 December 2012. Retrieved 29 January 2018. (last observation: 1994-12-31; arc: 35 days; Uncertainty: 8)
9. "Archive: Sentry Risk Table". NASA/JPL Near-Earth Object Program Office. 29 May 2013. Archived from the original on 29 May 2013.

External links

• List Of Aten Minor Planets (by designation), Minor Planet Center
• 1994 WR12 at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• 1994 WR12 at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical properties · Summary
• 1994 WR12 at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters