Age Estimation of Young Asteroid Pairs

In order to estimate the age, the work examined the probabilistic evolution of three young pairs of asteroids in close orbits: (87 887) 2000 SS286—(415 992) 2002 AT49, (320 025) 2007 DT76—(489 464) 2007 DP16, (21 436) Chaoyichi—(334 916) 2003 YK39. In the numerical simulation, along with gravitational disturbances, the Yarkovsky effect in the form of a secular drift of the orbital semimajor axis was taken into account. For each pair of asteroids, 25 evolution scenarios were considered, corresponding to different combinations of obliquities of the asteroids’ rotation axes and, correspondingly, different drift rates of the semimajor axes due to the Yarkovsky effect. For each asteroid, 1000 clones were generated. Age estimates were obtained based on analysis of moment distributions: (1) low relative-velocity close encounters of asteroids of pair to distances on the order of the Hill sphere at a relative speed of several units of the escape velocity and (2) achievement of minimum values of the Kholshevnikov metric, which characterizes the distance between orbits. The following age estimates for young asteroid pairs were obtained: (87 887) 2000 SS286 and (415 992) 2002 AT49 from 7.58 ± 0.04 to 8.80 ± 0.04 kyr; (320 025) 2007 DT76 and (489464) 2007 DP16 from 15.5 ± 1.0 to 58.6 ± 16.0 kyr; (21 436) Chaoyichi and (334 916) 2003 YK39 from 32.3 ± 0.1 to 102.6 ± 0.7 kyr.