2008 HJ
| Discovery | |
|---|---|
| Discovered by | LINEAR |
| Discovery site | Lincoln Lab ETS |
| Discovery date | 24 April 2008 |
| Designations | |
| NEO · Apollo[1] | |
| Orbital characteristics[1] | |
| Epoch 21 November 2025 (JD 2461000.5) | |
| Uncertainty parameter 6 | |
| Aphelion | 2.29639 AU (343.535 Gm) (Q) |
| Perihelion | 0.967561 AU (144.7451 Gm) (q) |
| 1.63198 AU (244.141 Gm) (a) | |
| Eccentricity | 0.40712 (e) |
| 2.08 yr (761.50 d) | |
| 139.306° (M) | |
| 0° 28m 21.907s /day (n) | |
| Inclination | 0.923627° (i) |
| 47.4545° (Ω) | |
| 204.2086° (ω) | |
| Earth MOID | 0.00185855 AU (278,035 km) |
| Jupiter MOID | 2.74944 AU (411.310 Gm) |
| Physical characteristics | |
| Dimensions | 12×24 m |
| Mass | 5 million kg (assumed) |
| 42.7 s (0.01185 h) | |
| 25.85[1] | |
2008 HJ is a sub-kilometer asteroid, classified as near-Earth object of the Apollo group.
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 also
[edit]References
[edit]- 1 2 3 4 "JPL Small-Body Database Browser: (2008 HJ)" (last observation: 2008-04-30; arc: 6 days; uncertainty: 6). Jet Propulsion Laboratory. Retrieved 30 March 2016.
- ↑ Record spin for new-found asteroid, BBC.com, 30 May 2008
- ↑ "Earth Impact Risk Summary: 2008 HJ". NASA/JPL Near-Earth Object Program Office. Retrieved 22 January 2018.
External links
[edit]- MPEC 2008-H26 : 2008 HJ (Discovery)
- 2008 HJ at NeoDyS-2, Near Earth Objects—Dynamic Site
- 2008 HJ at ESA–space situational awareness
- 2008 HJ at the JPL Small-Body Database
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