(277475) 2005 WK4
Near-Earth asteroid
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(277475) 2005 WK4, provisional designation 2005 WK4, is a stony, sub-kilometer asteroid, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group that passed Earth within 8.2 lunar distances on 8 August 2013.[7] It was discovered on 27 November 2005, by astronomers of the Siding Spring Survey at Siding Spring Observatory, Australia.[2]
2005 WK4 imaged 30 times by radar at Goldstone on 8 August 2013 | |
| Discovery[1][2] | |
|---|---|
| Discovered by | Siding Spring Srvy. |
| Discovery site | Siding Spring Obs. |
| Discovery date | 27 November 2005 |
| Designations | |
| (277475) 2005 WK4 | |
| 2005 WK4 | |
| Apollo · NEO · PHA[1][2] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 8.71 yr (3,180 days) |
| Aphelion | 1.2506 AU |
| Perihelion | 0.7707 AU |
| 1.0106 AU | |
| Eccentricity | 0.2374 |
| 1.02 yr (371 days) | |
| 81.040° | |
| 0° 58m 12.36s / day | |
| Inclination | 9.8433° |
| 138.14° | |
| 74.063° | |
| Earth MOID | 0.0037 AU · 1.4 LD |
| Physical characteristics | |
| Dimensions | 0.25±0.05 km[a] 0.284 km (calculated)[3] |
| 2.595±0.002 h[4] 2.7±0.1 h[a] 2.73±0.05 h[5] | |
| 0.20 (assumed)[3] | |
| Sk[6] · S (assumed)[3] B–V = 0.677±0.025[6] V–R = 0.446±0.019[6] V–I = 0.750±0.024[6] | |
| 20.1[1][3] | |
Description
In August 2013, 2005 WK4 was radar-imaged by the Deep Space Network dish at Goldstone Observatory, United States,[7] and had been observed previously at Arecibo Observatory in July 2012 (this was not a close approach though).[8]
Physical characteristics
2005 WK4 measures approximately 250 meters in diameter, and has a rotation period of 2.595 hours.[3][4][a] Its spectral type is that of an Sk-subtype, which transitions from the stony S-type to the uncommon K-type asteroids.[6]
See also
Notes
- Benner (2013): radiometric observations: mean diameter 0.25±0.05 km; rotation period 2.7±0.1 hours. Summary figures at the LCDB; also see NASA news report