2018 LA
2018 LA, also known as ZLAF9B2, was a small Apollo near-Earth asteroid 2.6–3.8 m (9–12 ft) in mean diameter that impacted the atmosphere with small fragments reaching the Earth at roughly 16:44 UTC (18:44 local time) on 2 June 2018 near the border of Botswana and South Africa. It had been discovered only 8 hours earlier by the Mount Lemmon Survey, Arizona and based on 1+1⁄2 hours of observations, was calculated to have a roughly 85% chance of impact likely somewhere between Australia and Madagascar.
Orbit and positions of 2018 LA, 30 days before collision | |
| Discovery | |
|---|---|
| Discovered by | Mount Lemmon Srvy. Richard Kowalski |
| Discovery site | Mount Lemmon Obs. |
| Discovery date | 2 June 2018 |
| Designations | |
MPC designation | 2018 LA |
Alternative designations | ZLAF9B2 (NEOCP) |
Minor planet category | NEO · Apollo |
| Orbital characteristics | |
| Epoch 2 June 2018 (JD 2458271.5) | |
| Uncertainty parameter 8 · 6 | |
| Observation arc | 3.8 hours (14 obs.) |
| Aphelion | 1.9709 AU |
| Perihelion | 0.7820 AU |
Semi-major axis | 1.3764 AU |
| Eccentricity | 0.4319 |
Orbital period (sidereal) | 1.61 yr (590 d) |
Mean anomaly | 326.73° |
Mean motion | 0° 36m 37.08s / day |
| Inclination | 4.2975° |
Longitude of ascending node | 71.870° |
| 2018-Jul-26 | |
| 256.05° | |
| Earth MOID | < 5000 km |
| Venus MOID | 0.0557 AU |
| Mars MOID | 0.0191 AU |
| Physical characteristics | |
Mean diameter | 1.6–5.2 m (5.2–17.1 ft) (est. 0.05–0.3) 2.6–3.8 m (8.5–12.5 ft) (est. impact energy) |
| Mass | 25–35 t (55,000–77,000 lbs.) |
| 0.15–0.30 (est. impact size) | |
| 18.3 (at discovery) | |
| 30.554 30.6 | |
Hours later, a report arrived to the American Meteor Society that an observer from Botswana had seen a bright fireball. Shortly after the impact, the Asteroid Terrestrial-impact Last Alert System (ATLAS) released observations obtained from Hawaii roughly 2 hours after the Mount Lemmon observations which confirmed that the asteroid had indeed impacted Earth on a grazing path as per the observed fireball. A preliminary analysis of the pre-impact evolution of this meteoroid suggests that it may be part of a dynamical grouping.