2007 WD5
2007 WD5 is an Apollo asteroid some 50 m (160 ft) in diameter and a Mars-crosser asteroid first observed on 20 November 2007, by Andrea Boattini of the Catalina Sky Survey. Early observations of 2007 WD5 caused excitement amongst the scientific community when it was estimated as having as high as a 1 in 25 chance of colliding with Mars on 30 January 2008. However, by 9 January 2008, additional observations allowed NASA's Near Earth Object Program (NEOP) to reduce the uncertainty region resulting in only a 1-in-10,000 chance of impact. 2007 WD5 most likely passed Mars at a distance of 6.5 Mars radii. Due to this relatively small distance and the uncertainty level of the prior observations, the gravitational effects of Mars on its trajectory are unknown and, according to Steven Chesley of NASA's Jet Propulsion Laboratory Near-Earth Object program, 2007 WD5 is currently considered 'lost' (see lost asteroids).
| Discovery | |
|---|---|
| Discovered by | Mount Lemmon Survey Andrea Boattini (unofficial credits) |
| Discovery date | 20 November 2007 |
| Designations | |
Minor planet category | NEO · Apollo Mars-crosser |
| Orbital characteristics | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 5 · 0 | |
| Aphelion | 3.9289 AU (587.76 Gm) |
| Perihelion | 0.991120 AU (148.2694 Gm) |
Semi-major axis | 2.4600 AU (368.01 Gm) |
| Eccentricity | 0.59711 |
Orbital period (sidereal) | 3.86 yr (1409.3 d) |
Average orbital speed | 12.5 km/s (27,900 mph) |
Mean anomaly | 49.267° |
Mean motion | 0° 15m 19.62s /day |
| Inclination | 2.4276° |
Longitude of ascending node | 68.491° |
| 309.622° | |
| Earth MOID | 0.0260299 AU (3.89402 Gm) |
| Physical characteristics | |
| Dimensions | 50 m (160 ft) |
| 24.3 | |