From horseshoe to quasi-satellite and back again: the curious dynamics of Earth co-orbital asteroid 2015 SO2

  • C. de la Fuente MarcosEmail author
  • R. de la Fuente Marcos
Original Article


Earth co-orbitals of the horseshoe type are interesting objects to study for practical reasons. They are relatively easy to access from our planet and that makes them attractive targets for sample return missions. Here, we show that near-Earth asteroid (NEA) 2015 SO2 is a transient co-orbital to the Earth that experiences a rather peculiar orbital evolution characterised by recurrent, alternating horseshoe and quasi-satellite episodes. It is currently following a horseshoe trajectory, the ninth asteroid known to do so. Besides moving inside the 1:1 mean motion resonance with the Earth, it is subjected to a Kozai resonance with the value of the argument of perihelion librating around 270°. Contrary to other NEAs, asteroid 2015 SO2 may have remained in the vicinity of Earth’s co-orbital region for a few hundreds of thousands of years.


Celestial mechanics Minor planets, asteroids: general Minor planets, asteroids: individual: 2015 SO2 Planets and satellites: individual: Earth 



We thank two anonymous referees for their constructive and helpful reports, and S.J. Aarseth for providing the main code used in this research. In preparation of this paper, we made use of the NASA Astrophysics Data System, the ASTRO-PH e-print server and the MPC data server.


  1. Aarseth, S.J.: Gravitational N-Body Simulations, p. 27. Cambridge University Press, Cambridge (2003) CrossRefzbMATHGoogle Scholar
  2. Avdyushev, V.A., Banschikova, M.A.: Sol. Syst. Res. 41, 413 (2007) CrossRefADSGoogle Scholar
  3. Boekholt, T., Portegies Zwart, S.: Comput. Astrophys. Cosmol. 2, 2 (2015) CrossRefADSGoogle Scholar
  4. Bordovitsyna, T., Avdyushev, V., Chernitsov, A.: Celest. Mech. Dyn. Astron. 80, 227 (2001) CrossRefADSzbMATHGoogle Scholar
  5. Brasser, R., Innanen, K.A., Connors, M., Veillet, C., Wiegert, P., Mikkola, S., Chodas, P.W.: Icarus 171, 102 (2004) CrossRefADSGoogle Scholar
  6. Brown, P.G., et al.: Nature 503, 238 (2013) ADSGoogle Scholar
  7. Christou, A.: Icarus 144, 1 (2000) CrossRefADSGoogle Scholar
  8. Christou, A.A., Asher, D.J.: Mon. Not. R. Astron. Soc. 414, 2965 (2011) CrossRefADSGoogle Scholar
  9. Connors, M.: Mon. Not. R. Astron. Soc. 437, L85 (2014) CrossRefADSGoogle Scholar
  10. Connors, M., Chodas, P., Mikkola, S., Wiegert, P., Veillet, C., Innanen, K.: Meteorit. Planet. Sci. 37, 1435 (2002) CrossRefADSGoogle Scholar
  11. Connors, M., Veillet, C., Brasser, R., Wiegert, P., Chodas, P., Mikkola, S., Innanen, K.: Meteorit. Planet. Sci. 39, 1251 (2004) CrossRefADSGoogle Scholar
  12. Connors, M., Wiegert, P., Veillet, C.: Nature 475, 481 (2011) CrossRefADSGoogle Scholar
  13. de la Fuente Marcos, C., de la Fuente Marcos, R.: Mon. Not. R. Astron. Soc. 427, 728 (2012) CrossRefADSGoogle Scholar
  14. de la Fuente Marcos, C., de la Fuente Marcos, R.: Mon. Not. R. Astron. Soc. 434, L1 (2013) CrossRefADSGoogle Scholar
  15. de la Fuente Marcos, C., de la Fuente Marcos, R.: Mon. Not. R. Astron. Soc. 445, 2985 (2014) CrossRefADSGoogle Scholar
  16. de la Fuente Marcos, C., de la Fuente Marcos, R.: Astron. Astrophys. 580, A109 (2015a) CrossRefGoogle Scholar
  17. de la Fuente Marcos, C., de la Fuente Marcos, R.: Mon. Not. R. Astron. Soc. 453, 1288 (2015b) CrossRefADSGoogle Scholar
  18. Elvis, M.: Nature 485, 549 (2012) CrossRefADSGoogle Scholar
  19. Elvis, M.: Planet. Space Sci. 91, 20 (2014) CrossRefADSGoogle Scholar
  20. García Yárnoz, D., Sanchez, J.P., McInnes, C.R.: Celest. Mech. Dyn. Astron. 116, 367 (2013) CrossRefADSGoogle Scholar
  21. Giorgini, J.D., et al.: Bull. Am. Astron. Soc. 28, 1158 (1996) ADSGoogle Scholar
  22. Harris, A.W., Drube, L.: Astrophys. J. 785, L4 (2014) CrossRefADSGoogle Scholar
  23. Hollabaugh, M., Everhart, E.: Astrophys. Lett. 15, 1 (1973) ADSGoogle Scholar
  24. Ito, T., Tanikawa, K.: Icarus 139, 336 (1999) CrossRefADSGoogle Scholar
  25. Kozai, Y.: Astron. J. 67, 591 (1962) MathSciNetCrossRefADSGoogle Scholar
  26. Lewis, J.S.: Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets, p. 82. Addison-Wesley, Reading (1996) Google Scholar
  27. Makino, J.: Astrophys. J. 369, 200 (1991) MathSciNetCrossRefADSGoogle Scholar
  28. Margot, J.L., Nicholson, P.D.: Bull. Am. Astron. Soc. 35, 1039 (2003) ADSGoogle Scholar
  29. Mikkola, S., Innanen, K., Wiegert, P., Connors, M., Brasser, R.: Mon. Not. R. Astron. Soc. 369, 15 (2006) CrossRefADSGoogle Scholar
  30. Mikuž, B., et al.:. MPEC 2015-S69 (2015) Google Scholar
  31. Morais, M.H.M., Morbidelli, A.: Icarus 160, 1 (2002) CrossRefADSGoogle Scholar
  32. Murray, C.D., Dermott, S.F.: Solar System Dynamics, p. 97. Cambridge University Press, Cambridge (1999) zbMATHGoogle Scholar
  33. Namouni, F.: Icarus 137, 293 (1999) CrossRefADSGoogle Scholar
  34. Namouni, F., Murray, C.D.: Celest. Mech. Dyn. Astron. 76, 131 (2000) CrossRefADSzbMATHGoogle Scholar
  35. Namouni, F., Christou, A.A., Murray, C.D.: Phys. Rev. Lett. 83, 2506 (1999) CrossRefADSGoogle Scholar
  36. Sitarski, G.: Acta Astron. 48, 547 (1998) ADSGoogle Scholar
  37. Sitarski, G.: Acta Astron. 49, 421 (1999) ADSGoogle Scholar
  38. Sitarski, G.: Acta Astron. 56, 283 (2006) ADSGoogle Scholar
  39. Stacey, R.G., Connors, M.: Planet. Space Sci. 57, 822 (2009) CrossRefADSGoogle Scholar
  40. Standish, E.M.: JPL Planetary and Lunar Ephemerides, DE405/LE405, Interoffice Memo. 312.F-98-048, Jet Propulsion Laboratory, Pasadena, CA, USA (1998) Google Scholar
  41. Tanikawa, K., Ito, T.: Publ. Astron. Soc. Jpn. 59, 989 (2007) CrossRefADSGoogle Scholar
  42. Wajer, P.: Icarus 209, 488 (2010) CrossRefADSGoogle Scholar
  43. Wiegert, P.A., Innanen, K.A., Mikkola, S.: Nature 387, 685 (1997) CrossRefADSGoogle Scholar
  44. Wiegert, P.A., Innanen, K.A., Mikkola, S.: Astron. J. 115, 2604 (1998) CrossRefADSGoogle Scholar
  45. Wiegert, P., Connors, M., Chodas, P., Veillet, C., Mikkola, S., Innanen, K.: American Geophysical Union, Fall Meeting 2002, P11A-0352 (2002) Google Scholar
  46. Wiegert, P.A., DeBoer, R., Brasser, R., Connors, M.: J. R. Astron. Soc. Can. 102, 52 (2008) Google Scholar
  47. Yeomans, D.K.: Bull. Am. Astron. Soc. 38, 1057 (2006) ADSGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  1. 1.MadridSpain

Personalised recommendations