Astronomy:2008 HJ
| Discovery | |
|---|---|
| Discovered by | LINEAR |
| Discovery site | Lincoln Lab ETS |
| Discovery date | 24 April 2008 |
| Designations | |
| 2008 HJ | |
| Minor planet category | NEO · Apollo[1] |
| Orbital characteristics[1] | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 6 | |
| |{{{apsis}}}|helion}} | 2.29553 astronomical unit|AU (343.406 Gm) (Q) |
| |{{{apsis}}}|helion}} | 0.968318 AU (144.8583 Gm) (q) |
| 1.63192 AU (244.132 Gm) (a) | |
| Eccentricity | 0.40664 (e) |
| Orbital period | 2.08 yr (761.46 d) |
| Mean anomaly | 237.912° (M) |
| Mean motion | 0° 28m 21.99s /day (n) |
| Inclination | 0.925579° (i) |
| Longitude of ascending node | 47.4700° (Ω) |
| 204.1346° (ω) | |
| Earth MOID | 0.00170917 AU (255,688 km) |
| Jupiter MOID | 2.75111 AU (411.560 Gm) |
| Physical characteristics | |
| Dimensions | 12×24 m |
| Mass | 5×106 kg (assumed) |
| Sidereal rotation period | 42.7 s (0.01185 h) |
| Absolute magnitude (H) | 25.8[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
References
- ↑ 1.0 1.1 1.2 1.3 "JPL Small-Body Database Browser: (2008 HJ)". Jet Propulsion Laboratory. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2008HJ. 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. https://cneos.jpl.nasa.gov/sentry/details.html#?des=2008%20HJ. Retrieved 2018-01-22.
External links
- MPEC 2008-H26 : 2008 HJ (Discovery)
- 2008 HJ at NeoDyS-2, Near Earth Objects—Dynamic Site
- Ephemeris · Obs prediction · Orbital info · MOID · Proper elements · Obs info · Close · Physical info · NEOCC
- 2008 HJ at ESA–space situational awareness
- 2008 HJ at the JPL Small-Body Database
 |  |
