(357439) 2004 BL86

(357439) 2004 BL86
Goldstone radar image of 2004 BL86 and its minor-planet moon
Discovery[1][2]
Discovered byLINEAR
Discovery siteLincoln Lab's ETS
Discovery date30 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 arc4,863 d (13.31 yr)
Aphelion2.1070 AU
Perihelion0.8974 AU
1.5022 AU
Eccentricity0.4026
673 d (1.84 yr)
169.27°
0° 32m 7.08s / day
Inclination23.775°
126.69°
311.45°
Known satellites1[4][5]
Earth MOID0.0092 AU (3.6 LD)
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-kilometer asteroid and binary system, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 300 meters (980 ft) in diameter. It was discovered on 30 January 2004 by astronomers of the Lincoln Near-Earth Asteroid Research at Lincoln 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]

2015 Earth approach

On 26 January 2015 at 16:20 UTC, 2004 BL86 passed 1,199,600 km (745,400 mi), or 3.1 lunar distances, from Earth.[11] The asteroid briefly peaked around apparent magnitude 9 and was near the celestial equator.[12] The asteroid was visible in telescopes with objectives of 100 mm (4 in) or larger; high-end binoculars under a dark sky may also have worked.[13] Near closest approach the asteroid was moving about 2.5 degrees per hour (2.5 arcseconds per second).[12][14] The asteroid came to opposition (furthest elongation in the sky from the Sun) on 27 January 2015 at 04:37 UTC.[12] Around 5:00 UTC, the asteroid was near M44 (the Beehive Cluster).[14]

The 26 January 2015 approach of 3.1 lunar distances was the closest approach of 2004 BL86 for at least the next 200 years.[11][15] For comparison, 2015 TB145, about twice the size of 2004 BL86, passed 486,800 km (302,500 mi), or 1.3 lunar distances, from Earth on 31 October 2015.[16]

Satellite

A minor-planet moon, provisionally designated S/2015 (357439) 1, was first detected by ground-based telescopes by Joe Pollock and Petr Pravec.[8][17] Observations by the Goldstone Deep Space Communications Complex and Green Bank Telescope confirmed that it is a binary 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]

Numbering and naming

This minor planet was numbered on 27 March 2013 (M.P.C. 83151).[18] As of 2020, it has not been named.[3]

  • Animation of 2004 BL86's orbit    Sun ·    Earth  ·   2004 BL86
    Animation of 2004 BL86's orbit
       Sun ·    Earth  ·   2004 BL86
  • 2004 BL86 safely passes Earth on 26 January 2015
    2004 BL86 safely passes Earth on 26 January 2015
  • Trajectory of 2004 BL86 during Earth close approach
    Trajectory of 2004 BL86 during Earth close approach
  • 2004 BL86 (star trail on left) near Xi Puppis
    2004 BL86 (star trail on left) near Xi Puppis

Notes

  1. ^ Radar Team 2015a: diameter primary 0.325±0.025 km. Diameter secondary 0.070 km. The satellites discovery is credited to Pollock et al.[8] Summary figures for (357439) 2004 BL86 at LCDB

References

  1. ^ a b c d "JPL Small-Body Database Browser: 357439 (2004 BL86)" (2017-05-24 last obs.). Jet Propulsion Laboratory. Retrieved 29 November 2017.
  2. ^ "MPEC 2004-B80 : 2004 BL86". IAU Minor Planet Center. 31 January 2004. Retrieved 7 June 2014. (K04B86L)
  3. ^ a b c "357439 (2004 BL86)". Minor Planet Center. Retrieved 30 September 2020.
  4. ^ a b c Johnston, Wm. Robert (31 January 2015). "Asteroids with Satellites Database – (357439) 2004 BL86". Johnston's Archive. Retrieved 29 November 2017.
  5. ^ a b c d e Agle, D. C. (26 January 2015). "Asteroid That Flew Past Earth Today Has Moon". NASA/Jet Propulsion Laboratory. Retrieved 29 November 2017.
  6. ^ a b c d Reddy, Vishnu; et al. (September 2015). "The Physical Characterization of the Potentially Hazardous Asteroid 2004 BL86: A Fragment of a Differentiated Asteroid". The Astrophysical Journal. 811 (1): 10. arXiv:1509.07122. Bibcode:2015ApJ...811...65R. doi:10.1088/0004-637X/811/1/65. S2CID 119260041.
  7. ^ a b c d e Birlan, M.; et al. (September 2015). "Characterization of (357439) 2004 BL86 on its close approach to Earth in 2015". Astronomy and Astrophysics. 581: 7. Bibcode:2015A&A...581A...3B. doi:10.1051/0004-6361/201526460.
  8. ^ a b c Pollock, J.; Pravec, P.; Oey, J.; Reichart, D. E.; Haislip, J. B.; LaCluyze, A. P. (January 2015). "(357439) 2004 BL_86". Central Bureau Electronic Telegrams. 4063 (4063): 1. Bibcode:2015CBET.4063....1P.
  9. ^ a b "LCDB Data for (357439)". Asteroid Lightcurve Database (LCDB). Retrieved 29 November 2017.
  10. ^ Franco, Lorenzo (July 2015). "Low Resolution Visible Reflectance Spectrum for NEA (357439) 2004 BL86". The Minor Planet Bulletin. 42 (3): 186–187. Bibcode:2015MPBu...42..186F. ISSN 1052-8091.
  11. ^ a b "JPL Close-Approach Data: 357439 (2004 BL86)" (last observation: 12 March 2013; arc: 9.11 years). NASA/Jet Propulsion Laboratory. Retrieved 7 June 2014.
  12. ^ a b c "(357439) 2004BL86 Ephemerides for 25 January 2015 through 29 January 2015". NEODyS. Retrieved 7 June 2014.
  13. ^ Musgrave, Ian (23 January 2015). "Seeing the Close Flyby of NEO 2004 BL86 26 - 27 January, 2015". Retrieved 28 January 2015.
  14. ^ a b MacRobert, Alan (22 January 2015). "Mountain-size Asteroid Glides Past Earth". Sky & Telescope. Retrieved 23 January 2015.
  15. ^ Busch, Michael (7 February 2015). "Final post-flyby update..." Twitter.com. Retrieved 7 February 2015.
  16. ^ "JPL Close-Approach Data: 2015 TB145" (last observation: 1 November 2015; arc: 22 days). NASA/Jet Propulsion Laboratory. Retrieved 2 December 2015.
  17. ^ "Image Release: High-Def Radar Images of Near-Earth Asteroid". National Radio Astronomy Observatory. 30 January 2015. Retrieved 30 January 2015.
  18. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 29 November 2017.
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