Yarkovsky effect detection and updated impact hazard assessment for near-Earth asteroid (410777) 2009 FD

Abstract

Aims. Near-Earth asteroid (410777) 2009 FD is a potentially hazardous asteroid with possible (though unlikely) impacts on Earth at the end of the twenty-second century. The astrometry collected during the 2019 apparition provides information on the trajectory of (410777) by constraining the Yarkovsky effect, which is the main source of uncertainty for future predictions, and improving the impact hazard assessment. Methods. We included the Yarkovsky effect in the force model and estimated its magnitude from the fit to the optical and radar astrometric data of (410777). We performed the hazard assessment for (410777) over 200 years using two independent approaches: the NEODyS group adopted a generalisation of the Line Of Variations method in a seven-dimensional space, and the JPL team used the Multi-Layer Clustered Sampling technique. Results. We obtain a 4σ detection of the Yarkovsky effect acting on (410777), which corresponds to a semimajor axis drift of (3.8 ± 0.9) × 10−3 au Myr−1. In the hazard results of both teams, the main impact possibility in 2185 is ruled out and the only remaining one is in 2190, but with a probability lower than 10−8.