Discovery [1] [2] | |
---|---|
Discovered by | Siding Spring Survey |
Discovery site | Siding Spring Obs. |
Discovery date | 5 June 2005 |
Designations | |
2005 LW3 | |
NEO · Apollo · PHA | |
Orbital characteristics [3] | |
Epoch 25 February 2023 ( JD 2460000.5) | |
Uncertainty parameter 0 | |
Observation arc | 17.49 yr (6,389 days) [1] |
Aphelion | 2.106 AU |
Perihelion | 0.771 AU |
1.439 AU | |
Eccentricity | 0.4638 |
1.73 yr (630.3 days) | |
81.385 ° | |
0° 34m 16.171s / day | |
Inclination | 6.021° |
59.587° | |
5 October 2022 | |
288.663° | |
Earth MOID | 0.001397 AU (209,000 km; 0.544 LD) |
Jupiter MOID | 3.335 AU |
Physical characteristics | |
Mean diameter | 400 m (primary) [4] |
3.6 h [4] | |
0.02 [5] | |
21.89 [3] · 21.68 [1] | |
2005 LW3 is a binary near-Earth asteroid classified as a potentially hazardous object of the Apollo group. It was discovered on 5 June 2005 by the Siding Spring Survey at Siding Spring Observatory in Australia. [2] It made a close approach of 2.97 lunar distances (1.14×10 6 km; 0.71×10 6 mi) from Earth on 23 November 2022, reaching a peak brightness of apparent magnitude 13 as it passed over the northern celestial hemisphere sky. [1] It was extensively observed by astronomers worldwide during the close approach, and radar observations by NASA's Goldstone Solar System Radar in California discovered a 100 m (330 ft)-wide natural satellite orbiting the asteroid at a wide separation of 4 km (2.5 mi). [6] [7]
Goldstone Solar System Radar observations in November 2022 resolved the shape of 2005 LW3, revealing a body 400 m (1,300 ft) in diameter—larger than its previously expected diameter of 150 m (490 ft). [4] [7] For an absolute magnitude of 21.9, this radar-measured diameter indicates that 2005 LW3 has a very low geometric albedo of 0.02. [5] These radar observations also determined a rotation period of 3.6 hours for 2005 LW3. [4]
The satellite of 2005 LW3 was discovered by a team of astronomers [a] using Goldstone Solar System Radar observations from 23–27 November 2022. The satellite appears elongated, with equatorial dimensions of 100 m × 50 m (330 ft × 160 ft). [4] The satellite is widely separated from 2005 LW3 (the primary body of the system) at a semi-major axis of about 4 km (2.5 mi), [4] which is around 17% of the primary's Hill radius (24 km or 15 mi for an assumed primary density of 1.6 g/cm3). [5] The satellite's discovery was announced in a Central Bureau Electronic Telegram on 10 December 2022. [4]