Open main menu

2008 HJ is a sub-kilometer asteroid, classified as near-Earth object of the Apollo group.

2008 HJ
Discovered byLINEAR
Discovery siteLincoln Lab ETS
Discovery date24 April 2008
MPC designation2008 HJ
NEO · Apollo[1]
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 6
Aphelion2.29553 AU (343.406 Gm) (Q)
Perihelion0.968318 AU (144.8583 Gm) (q)
1.63192 AU (244.132 Gm) (a)
Eccentricity0.40664 (e)
2.08 yr (761.46 d)
237.912° (M)
0° 28m 21.99s /day (n)
Inclination0.925579° (i)
47.4700° (Ω)
204.1346° (ω)
Earth MOID0.00170917 AU (255,688 km)
Jupiter MOID2.75111 AU (411.560 Gm)
Physical characteristics
Dimensions12×24 m
Mass5×106 kg (assumed)
42.7 s (0.01185 h)

It was discovered by Lincoln Laboratory ETS, New Mexico. Observers M. Bezpalko, D. Torres, R. Kracke, G. Spitz, J. Kistler. Richard Miles using the Faulkes Telescope South at Siding Spring Observatory, Australia determined that the asteroid rotates rapidly. It measures only 12 m by 24 m and is very dense, having a mass of about 5,000 tonnes. If the asteroid were not dense, it is probable that the rapid rotation would cause the asteroid to disrupt and fly apart.

At the time of discovery, 2008 HJ had the smallest known rotation period in the Solar System, completing one revolution every 42.7 seconds.[1][2]

It is listed on the Sentry Risk Table with a 1 in 17,000 chance of impacting Earth on May 2, 2081.[3] An impact from this object would be comparable to the Chelyabinsk meteor.

See alsoEdit


  1. ^ a b c d "JPL Small-Body Database Browser: (2008 HJ)" (last observation: 2008-04-30; arc: 6 days; uncertainty: 6). Jet Propulsion Laboratory. Retrieved 30 March 2016.
  2. ^ Record spin for new-found asteroid,, 30 May 2008
  3. ^ "Earth Impact Risk Summary: 2008 HJ". NASA/JPL Near-Earth Object Program Office. Retrieved 22 January 2018.

External linksEdit