2001 SD365 and (340076) 2005 WX6

Based on nominal orbital parameters, this is the result of a backward integration performed with Mercury6 (*) Bulirsch–Stoer run with a 0.05-day step, 1e-12 accuracy, and outputs every 100 days, integrating from JD 2461000.5 backward for 100 M days (~0.27 Myr)

(*) Chambers, J.E. 1999, “A Hybrid Symplectic Integrator that Permits Close Encounters between Massive Bodies,”

The following plot shows the relative velocity and distance at the time when the relative velocity was minimum (other previous minima might of course be present but the uncertainty is very high):

Best wishes,

Alessandro Odasso

2016 EF349 and (51498) 2001 FW80

 Based on nominal orbital parameters, this is the result of a backward integration performed with Mercury6 (*) Bulirsch–Stoer run with a 0.05-day step, 1e-12 accuracy, and outputs every 100 days, integrating from JD 2461000.5 backward for 100 M days (~0.27 Myr)

(*) Chambers, J.E. 1999, “A Hybrid Symplectic Integrator that Permits Close Encounters between Massive Bodies,”

The following plot shows the relative velocity and distance following the time when the relative velocity was minimum (other previous minima might of course be present but the uncertainty is very high):

Best wishes,

Alessandro Odasso

2014 QS487 and (48514) 1993 FN22

Based on nominal orbital parameters, this is the result of a backward integration performed with Mercury6 (*) Bulirsch–Stoer run with a 0.05-day step, 1e-12 accuracy, and outputs every 100 days, integrating from JD 2461000.5 backward for 100 M days (~0.27 Myr)

(*) Chambers, J.E. 1999, “A Hybrid Symplectic Integrator that Permits Close Encounters between Massive Bodies,”

The following plot shows the relative velocity and distance following the time when the relative velocity was minimum:

Best wishes,

Alessandro Odasso

(47162) Chicomendez = 1998 HS85 = 1999 TH6 and 2008 EA177

Potentially interesting couple:

2021 KT21 and 2004 GZ13

Backward simulation performed with Mercury6 ``A Hybrid Symplectic Integrator that Permits Close Encounters between Massive Bodies''. Monthly Notices of the Royal Astronomical Society, vol 304, pp793-799. 

Simulation based on nominal orbital paramters (21st March 2024)

Simulation parameters

)O+_06 Integration parameters  (WARNING: Do not delete this line!!)

) Lines beginning with `)' are ignored.

)---------------------------------------------------------------------

) Important integration parameters:

)---------------------------------------------------------------------

 algorithm (MVS, BS, BS2, RADAU, HYBRID etc) = BS

 start time (days)= 2460309.50000 

 stop time (days) = -1e8

 output interval (days) = 100

 timestep (days) = 0.05

 accuracy parameter=1.d-12

Simulation Result

Following a comment from Adrien Coffinet, here is a forward simulation to show that as correctly guessed, the two asteroids might be again in a similar orbital configuration about 20K years from now:

2023 SP50 and 152737 (1998 WF28)

 Backward simulation

Mercury6 package by J.E.Chambers (1999) ``A Hybrid Symplectic Integrator that Permits Close Encounters between Massive Bodies''. Monthly Notices of the Royal Astronomical Society, vol 304, pp793-799. 

)---------------------------------------------------------------------

) Important integration parameters:

)---------------------------------------------------------------------

 algorithm (MVS, BS, BS2, RADAU, HYBRID etc) = BS

 start time (days)=  2460106.5

) stop time (days) = 102458000.5

 stop time (days) = -1e8

 output interval (days) = 100

 timestep (days) = 0.05

 accuracy parameter=1.d-12

Result

2022 QZ273 and 2002 RZ12

Backward simulation

Mercury6 package by J.E.Chambers (1999) ``A Hybrid Symplectic Integrator that Permits Close Encounters between Massive Bodies''. Monthly Notices of the Royal Astronomical Society, vol 304, pp793-799. 

)---------------------------------------------------------------------

) Important integration parameters:

)---------------------------------------------------------------------

 algorithm (MVS, BS, BS2, RADAU, HYBRID etc) = BS

 start time (days)=  2460106.5

) stop time (days) = 102458000.5

 stop time (days) = -1e8

 output interval (days) = 1

 timestep (days) = 0.05

 accuracy parameter=1.d-12

Result