astro.wikisort.org - Asteroid

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. 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	6152017 km	± 74 km[6]
2046-11-25	1623763 km	± 42 km
2190-11-23	6450000 km	± 219 thousand km[7]

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° 29m 45.96s / 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	2.9×109 kg (est.)[4]
Absolute magnitude (H)	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 0.0018 AU (269,000 km), which translates into 0.7 lunar distances.[3] On 25 November 2046, it will pass 1623763 km from Earth with an uncertainty of ±42 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).

See also

• Lost asteroids

References

External links

• List Of Aten Minor Planets (by designation), Minor Planet Center
• 1994 WR12 at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemeris · Obs prediction · Orbital info · MOID · Proper elements · Obs info · Close · Physical info · NEOCC
• 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 diagram · Orbital elements · Physical parameters

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