Celestial Mechanics

The closest quasi-satellite to Earth

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Science  02 Sep 2016:
Vol. 353, Issue 6303, pp. 1001
DOI: 10.1126/science.353.6303.1001-b

A quasi-satellite orbits close to a planet, circling the Sun with the same orbital period, but it is not gravitationally bound to the planet. The fifth known quasi-satellite of Earth was discovered earlier this year: an asteroid with the snappy name (469219) 2016 HO3. In a recent study, de la Fuente Marcos and de la Fuente Marcos investigated its orbit with numerical simulations, showing that it will remain an Earth quasi-satellite for a few centuries. The asteroid, which is a few dozen meters across, stays between 38 and 100 times as far away from Earth as the Moon. This proximity and its low relative velocity make the object a tempting target for a visit by a sample-return mission—or even by astronauts.

Mon. Not. R. Astron. Soc. 10.1093/mnras/stw1972 (2016).

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