 | |
| Discovery[1][2] | |
|---|---|
| Discovered by | LINEAR |
| Discovery site | Lincoln Lab's ETS |
| Discovery date | 30 January 2004 |
| Designations | |
| (357439)2004 BL86 | |
| NEO · PHA · Apollo[1][3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 4,863 d (13.31 yr) |
| Aphelion | 2.1070AU |
| Perihelion | 0.8974 AU |
| 1.5022 AU | |
| Eccentricity | 0.4026 |
| 673 d (1.84 yr) | |
| 169.27° | |
| 0° 32m 7.08s / day | |
| Inclination | 23.775° |
| 126.69° | |
| 311.45° | |
| Knownsatellites | 1[4][5] |
| Earth MOID | 0.0092 AU (3.6LD) |
| Physical characteristics | |
| 0.263±0.026 km[6] 0.290±0.030 km[7] 0.325±0.025 km[5][a] | |
| 2.620±0.001 h[6] 2.6205±0.0003 h[8] 2.637±0.024 h[7] | |
| 0.40[7] 0.40±0.08[6] | |
| V[7][9][10] | |
| 19.05[9] 19.3[1][7] 19.51±0.02[6] | |
(357439) 2004 BL86 is a bright sub-kilometerasteroid andbinary system, classified as anear-Earth object andpotentially hazardous asteroid of theApollo group, approximately 300 meters (980 ft) in diameter. It was discovered on 30 January 2004 by astronomers of theLincoln Near-Earth Asteroid Research atLincoln Laboratory's Experimental Test Site near Socorro, New Mexico.[3] Its 70-meter (200 ft)moon was discovered during the asteroid's close approach to the Earth in January 2015.[4][5]
On 26 January 2015 at 16:20 UTC,2004 BL86 passed 1,199,600 km (745,400 mi), or 3.1lunar distances, from Earth.[11] The asteroid briefly peaked aroundapparent magnitude 9 and was near thecelestial equator.[12] The asteroid was visible intelescopes withobjectives of 100 mm (4 in) or larger; high-endbinoculars under a dark sky may also have worked.[13] Near closest approach the asteroid was moving about 2.5 degrees per hour (2.5arcseconds per second).[12][14] The asteroid came toopposition (furthestelongation in the sky from the Sun) on 27 January 2015 at 04:37 UTC.[12] Around 5:00 UTC, the asteroid was near M44 (theBeehive Cluster).[14]
The 26 January 2015 approach of 3.1 lunar distances was the closest approach of2004 BL86 for at least the next 200 years.[11][15] For comparison,2015 TB145, about twice the size of2004 BL86, passed 486,800 km (302,500 mi), or 1.3 lunar distances, from Earth on 31 October 2015.[16]
Aminor-planet moon orbiting(357439) 2004 BL86 was first detected by ground-based telescopes by Joe Pollock andPetr Pravec.[8][17] Observations by theGoldstone Deep Space Communications Complex andGreen Bank Telescope confirmed that it is abinary asteroid with a secondary roughly 70 meters (200 ft) across.[5] The secondary is estimated to orbit at least 500 meters (1,600 ft) from the primary.[4] About 16% of asteroids over 200 meters (660 ft) in diameter are thought to be binaries.[5]
Thisminor planet was numbered on 27 March 2013 (M.P.C. 83151).[18] As of 2020, it has not been named.[3]
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