2013 BS45

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2013 BS45
Discovered by James V. Scotti (Spacewatch)
Discovery date January 20, 2013
MPC designation 2013 BS45
Aten NEO,[1][2]
Earth crosser
Orbital characteristics[2][3][4]
Epoch December 9, 2014 (JD 2457000.5)
Aphelion 1.0770226 AU
Perihelion 0.9103335 AU
0.9936780 AU
Eccentricity 0.0838748
0.99 y (361.7986 d)
Inclination 0.77337°
Physical characteristics
Dimensions 20–40 m[a][5]

2013 BS45 (also written 2013 BS45) is a horseshoe companion to the Earth like 3753 Cruithne.[6] Like Cruithne, it does not orbit the Earth and at times it is on the other side of the Sun.

Discovery, orbit and physical properties[edit]

2013 BS45 was discovered by James V. Scotti on January 20, 2013 observing for the Spacewatch project from Kitt Peak (KPNO).[7][8] Its orbit is characterized by low eccentricity (0.084), low inclination (0.77º) and a semi-major axis of 0.993 AU;[8] it is the most Earth-like among those of asteroids moving in Earth-like orbits.[6] Upon discovery, it was classified as an Aten asteroid but also an Earth crosser by the Minor Planet Center. Its orbit is well determined; as of August 26, 2015 its orbit is based on 96 observations spanning a data-arc of 375 days.[2] 2013 BS45 has an absolute magnitude of 25.9 which gives a characteristic diameter of 30 m.[5] Radar observations indicate that it may be a very rapid rotator with a period of just a few minutes.

Horseshoe companion to the Earth and orbital evolution[edit]

Recent calculations indicate that it follows a horseshoe orbit with respect to the Earth.[6] Its orbital evolution is highly chaotic and its orbit is difficult to predict beyond a few thousand years.[6] As for the available data, it had its closest encounter ever with Earth on February 12, 2013 at 0.013 AU, closer than in 1934, the previously closest approach at 0.014 AU. The next approach closer than 0.020  will take place on September 2, 2090, at 0.016 AU.[2] Its orbit matches the expected properties of that of an object in the Arjuna-class.[9]


It may have been originated within the Venus-Earth-Mars region or in the main asteroid belt like other Near-Earth Objects, then transition to Amor-class asteroid before entering Earth's co-orbital region.[6]

See also[edit]


  • ^ This is assuming an albedo of 0.20–0.04.


  1. ^ "List Of Aten Minor Planets". Minor Planet Center. Retrieved 27 August 2015. 
  2. ^ a b c d e 2013 BS45 at the JPL Small-Body Database
  3. ^ "2013 BS45 – Summary". AstDys-2, Asteroids – Dynamic Site. Retrieved 11 May 2013. 
  4. ^ "2013 BS45 – Summary". NEODyS-2, Near Earth Objects – Dynamic Site. Retrieved 11 May 2013. 
  5. ^ a b "Absolute-magnitude conversion table (H)". NASA. 27 August 2015. 
  6. ^ a b c d e de la Fuente Marcos, C.; de la Fuente Marcos, R. (July 2013). "A resonant family of dynamically cold small bodies in the near-Earth asteroid belt". Monthly Notices of the Royal Astronomical Society: Letters 434 (1): L1–L5. arXiv:1305.2825. Bibcode:2013MNRAS.434L...1D. doi:10.1093/mnrasl/slt062. 
  7. ^ Discovery MPEC
  8. ^ a b "2013 BS45". MPC (last obs: 2014-01-30.0). Retrieved 26 August 2015. 
  9. ^ de la Fuente Marcos, C.; de la Fuente Marcos, R. (February 12, 2015). "Geometric characterization of the Arjuna orbital domain". Astronomische Nachrichten 336 (1): 5–22. arXiv:1410.4104. Bibcode:2015AN....336....5D. doi:10.1002/asna.201412133. 
Further reading

External links[edit]