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Discovery

2015 SO2 was discovered on 21 September 2015 by B. Mikuž observing with the 0.6-m f/3.3 Cichocki telescope at the Črni Vrh Observatory in Slovenia.²³ As of 30 November 2015, it has been observed 84 times with an observation arc of 9 days.⁴

Orbit and orbital evolution

2015 SO2 is currently an Aten asteroid (Earth-crossing but with a period less than a year). Its semi-major axis (currently 0.999115 AU) is similar to that of Earth (0.99957 AU), but it has a relatively low eccentricity (0.108105) and moderate orbital inclination (9.181°). Gravitational interaction with Earth causes its orbit to change so that its average period is one year. It alternates between being an Aten asteroid and being an Apollo asteroid, changing dynamical status every 113 years approximately. As of 30 November 2015, this object is the 14th known Earth co-orbital and the 9th known object following a horseshoe path with respect to our planet. Its orbital evolution is characterized by alternating horseshoe and quasi-satellite episodes.⁵

Physical properties

With an absolute magnitude of 23.9, it has a diameter in the range of 50–111 meters (for an assumed albedo range of 0.04–0.20, respectively).⁶

See also

• 54509 YORP
• (419624) 2010 SO16
• 3753 Cruithne

Notes

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

• Understanding the Distribution of Near-Earth Asteroids Bottke, W. F., Jedicke, R., Morbidelli, A., Petit, J.-M., Gladman, B. 2000, Science, Vol. 288, Issue 5474, pp. 2190–2194.
• A Numerical Survey of Transient Co-orbitals of the Terrestrial Planets Christou, A. A. 2000, Icarus, Vol. 144, Issue 1, pp. 1–20.
• Debiased Orbital and Absolute Magnitude Distribution of the Near-Earth Objects Bottke, W. F., Morbidelli, A., Jedicke, R., Petit, J.-M., Levison, H. F., Michel, P., Metcalfe, T. S. 2002, Icarus, Vol. 156, Issue 2, pp. 399–433.
• Transient co-orbital asteroids Brasser, R., Innanen, K. A., Connors, M., Veillet, C., Wiegert, P., Mikkola, S., Chodas, P. W. 2004, Icarus, Vol. 171, Issue 1, pp. 102–109.
• From horseshoe to quasi-satellite and back again: the curious dynamics of Earth co-orbital asteroid 2015 SO2 de la Fuente Marcos, C., de la Fuente Marcos, R. 2016, Astrophysics and Space Science, Vol. 361, Issue 1, article 16 (10 pp).

External links

• Discovery MPEC
• 2015 SO2 data at MPC
• Crni Vrh Observatory News
• Discovery image
• The 60-cm Cichocki Sky Survey Telescope
• 2015 SO2 at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• 2015 SO2 at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical properties · Summary
• 2015 SO2 at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

References

1. de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (2016). "From horseshoe to quasi-satellite and back again: the curious dynamics of Earth co-orbital asteroid 2015 SO2". Astrophysics and Space Science. 361 (1): 16. arXiv:1511.08360. Bibcode:2016Ap&SS.361...16D. doi:10.1007/s10509-015-2597-8. S2CID 189842725. /wiki/Astrophysics_and_Space_Science ↩

2. Discovery MPEC http://www.minorplanetcenter.net/mpec/K15/K15S69.html ↩

3. News release http://www.observatorij.org/News/News.html ↩

4. "2015 SO2". JPL Small-Body Database. Jet Propulsion Laboratory. SPK-ID: 3728565. Retrieved 4 April 2016. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3728565 ↩

5. de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (2016). "From horseshoe to quasi-satellite and back again: the curious dynamics of Earth co-orbital asteroid 2015 SO2". Astrophysics and Space Science. 361 (1): 16. arXiv:1511.08360. Bibcode:2016Ap&SS.361...16D. doi:10.1007/s10509-015-2597-8. S2CID 189842725. /wiki/Astrophysics_and_Space_Science ↩

6. "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 16 February 2018. https://cneos.jpl.nasa.gov/tools/ast_size_est.html ↩