Possible Close Approach of 2016 WM1

[PMSchu]

Hi BMD,

Check out the Orbit Viewer for this one at the CNEOS website. Step through the position in 1-day intervals & imagine that the NEO is 4 days behind the CNEOS's predicted position. Things get really close. Who to believe? As noted, CNEOS is still using the elements from 2016 Nov 22.

I did some checking at MPC & apparently, they do apply perturbations to their elements calculations. Here's the MPC's entry for this NEO: [attachment=2379]

The description of the perturbation info is given on their website here: https://minorplanetcenter.net/iau/info/Perturbers.html

2016 WM1 uses the default perturbation settings shown here:

Some examples of coarse and precise indicators are:

  Coarse  Precise    Perturbers (Mercury-Neptune+...)

    M-c      08      Ceres, EM barycenter
    M-c      0E      Ceres, Earth, Moon
    M-p      16      Pallas, Earth, Moon    [NOT RECOMMENDED]
    M-p      18      Ceres, Pallas, EM barycenter
    M-p      1E      Ceres, Pallas, Earth, Moon
    M-v      38      Ceres, Pallas, Vesta, EM barycenter
    M-v      3E      Ceres, Pallas, Vesta, Earth, Moon
    M-e      78      Ceres, Pallas, Vesta, Eunomia, EM barycenter
    M-e      7E      Ceres, Pallas, Vesta, Eunomia, Earth, Moon
    M-h      39      Ceres, Pallas, Vesta, Hygiea, EM barycenter
The default for Minor Planet Center orbits will henceforth be h (DE403), M-v (coarse) and 38 or 3E (precise, depending on whether the object is an earth-approacher or not). Additional perturbers will be added as necessary.


Hopefully this means that the MPC's elements include perturbations & that they're more accurate than what CNEOS is showing using elements from 2016.

There sure is a lot to learn about these objects. Very fascinating. I have no idea where this thing will be in 4 days.

Phil S.