Sholz's star entered the Oort cloud ~70kya

[jim mcnamara]

https://phys.org/news/2018-03-evidence-star-disturbed-prehistory-solar.html
https://academic.oup.com/mnrasl/article-abstract/476/1/L1/4840245?redirectedFrom=fulltext (abstract)
R. de la Fuentes, S. J Aarseth

Where the Solar system meets the solar neighbourhood: patterns in the distribution of radiants of observed hyperbolic minor bodies

Based on an earlier paper (E. Mamajek 2015) that indicated Sholz's star passed very close or into the outer edges of the Oort Cloud, so the Fuentes et al looked at the radiant for 340 Solar System objects with hyperbolic orbits. They further focused on 8 such objects.

They posit radiants for these objects should be scattered all round our sky. Some were scattered, some were clumped close to a single radiant. They link that effect to Sholz's start (small red/smaller brown dwarf binary) star entering the Oort Cloud and coming within ~.0.6 of the sun, ~70,000 years ago.

My only question so far: When I talked with one of the developers of some Maris astronomical software in 1998, he indicated that calculating historical positions for many objects in the Solar System more than 10,000 you was very problematic. We must have improved drastically since then? I know a lot of work at NASA on the NEO (Near Earth Object) database involves longer term orbit predictions for these kinds of objects -a few hundred years maybe, but uncertainty still reigns to some degree. Example: Bennu asteroid and estimated 2035 (? pick a date) position. The accuracy required for an Earth impact estimate is substantially different from getting the position of a star coming near the Oort Cloud, but the concept remains, since the time frames are orders of magnitude apart.
.
See: https://en.wikipedia.org/wiki/101955_Bennu
https://www.asteroidmission.org/why-bennu/

 

[.Scott]

When you attempt to backtrack an objects trajectory, every time it encounters a gravitational body, precision is lost.
For example, is you know the position of the object to within a mile as it approaches a planet, it's new trajectory will diverge by some angle based on where within that mile is was actually positioned.

In contrast, an object that simply passes through our solar system and then continues on without further encounters, will follow a more predictable path.