2009 SH2 orbits the Sun at an average distance of 0.99 AU once every 360 days, or approximately 0.99 years. Its orbit has an eccentricity of 0.09 and an inclination of 7° with respect to the ecliptic plane. Over the course of its orbit, its distance from the Sun ranges from 0.90 AU at perihelion to 1.08 AU at aphelion, crossing the orbit of Earth. Since its orbit crosses that of Earth's while having a semi-major axis less than 1 AU, 2009 SH2 is classified as an Aten asteroid. Its nominal orbit has a small minimum orbit intersection distance approximately 0.0006 AU (90,000 km; 56,000 mi) from Earth's orbital path and periodically makes close approaches to Earth.[4]
In 2013, astronomers Carlos and Raúl de la Fuente Marcos identified 2009 SH2 to be in a co-orbital configuration with Earth, a type of 1:1 orbital resonance where the asteroid appears to librate around Earth's path in a horseshoe orbit when viewed in a corotating reference frame with Earth. The co-orbital state of 2009 SH2 is only temporary as it has entered it about 30 years ago and will leave it in about 100 years into the future.[3]
Physical characteristics
Based on an magnitude-to-diameter conversion and a measured absolute magnitude of 24.9, 2009 SH2 measures between 30 and 60 meters in diameter for an assumed geometric albedo of 0.25 and 0.05, respectively.[2][5] A rotation period of 1.26 h has been tentatively measured from its lightcurve.[4]
^"2009SH2 Ephemerides". Near Earth Objects – Dynamic Site (Ephemerides at discovery (obs. code E12)). Department of Mathematics, University of Pisa, Italy. Retrieved 12 February 2021.
External links
2009 SH2 at NeoDyS-2, Near Earth Objects—Dynamic Site