astro
Thursday, October 23, 2025
P/2025 D3 (PANSTARRS)
Wednesday, October 1, 2025
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):
Alessandro Odasso
Sunday, September 21, 2025
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
Tuesday, November 26, 2024
Thursday, March 21, 2024
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
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:
Monday, February 5, 2024
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








