 | |
| Discovery[1] | |
|---|---|
| Discovered by | LONEOS |
| Discovery date | 30 April 2005 |
| Designations | |
| Orbital characteristics[2] | |
| Epoch 3 May 2005 (JD 2453493.5) | |
| Uncertainty parameter 9 | |
| Aphelion | 3.5707 AU (534.17 Gm) |
| Perihelion | 0.070657 AU (10.5701 Gm) |
| 1.8207 AU (272.37 Gm) | |
| Eccentricity | 0.96119 |
| 2.46 yr (897.30 d) | |
| 341.42° | |
| 0° 24m 4.32s /day | |
| Inclination | 8.3967° |
| 63.790° | |
| 309.01° | |
| Earth MOID | 0.0615074 AU (9.20138 Gm) |
| Jupiter MOID | 1.92798 AU (288.422 Gm) |
| Physical characteristics | |
| Dimensions | 210–480 m[3] |
| 20.7 | |
2005 HC4 is the asteroid with the smallest known perihelion of any known object orbiting the Sun (except sungrazing comets). Its extreme orbital eccentricity brings it to within 0.071 AU of the Sun (23% of Mercury's perihelion) and takes it as far as 3.562 AU from the Sun (well beyond the orbit of Mars). Due to its very small perihelion and comparably large aphelion, 2005 HC4 achieves the fastest speed of any known asteroid bound to the Solar System with a velocity of 157 km/s (565,000 km/h; 351,000 mi/h) at perihelion[4] (there are comets, however, which obtain much higher speeds).
