* Astronomy

Title: Asteroid 2012 XE133, a transient companion to Venus
Authors: C. de la Fuente Marcos, R. de la Fuente Marcos

Apart from Mercury that has no known co-orbital companions, Venus remains as the inner planet that hosts the smallest number of known co-orbitals, 2: (322756) 2001 CK32 and 2002 VE68. Both objects have absolute magnitudes 18 < H < 21 and were identified as Venus co-orbitals in 2004. Here, we analyse the orbit of the recently discovered asteroid 2012 XE133 with H = 23.5 mag to conclude that it is a new Venus co-orbital currently following a transitional trajectory between Venus' Lagrangian points L5 and L3. The object could have been a 1:1 librator for several thousand years and it may leave the resonance with Venus within the next few hundred years, after a close encounter with the Earth. Our calculations show that its dynamical status as co-orbital, as well as that of the 2 previously known Venus co-orbitals, is controlled by the Earth-Moon system with Mercury playing a secondary role. The 3 temporary co-orbitals follow rather chaotic but similar trajectories with e-folding times of order of 100 yr. Out of the three co-orbitals, 2012 XE133 currently follows the most perturbed path. An actual collision with the Earth during the next 10000 years cannot be discarded. Extrapolation of the number distribution of Venus co-orbitals as a function of the absolute magnitude suggests that dozens of objects similar to 2012 XE133 could be transient companions to Venus. Some additional objects that were or will be transient co-orbitals to Venus are also briefly discussed.

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