Would the Collision of Gliese 710 with the Oort Cloud Put us at Risk ?

[APODman]

Recently calculations made by Russian astronomer Vadim Bobylev tell us that the star Gliese 710 will be the next star to perform a close encounter with our solar system at about 1.4 million years.
Bobylev also estimated that there is little possibility that the star crosses the Oort cloud that could lead to the ejection of comets toward the inner solar system caused a new Heavy Bombardment on Earth:

- http://www.technologyreview.com/blog/arxiv/24917/
- http://arxiv.org/abs/1003.2160

But I have doubts about the possibility that Gliese 710 (which is estimated to cross into the Oort Cloud) is capable of destabilizing and launch a "barrage" of cometary objects from the Oort that can cause risk to Earth.
I think this cause the star SAO 128711 approaches at distances smaller than is calculated for Gliese 710 and yet the craters with ages between 1 and 0.3 million years old on Earth are few compared to, for example, the number of craters in the range of 500 million years:

- http://www.unb.ca/passc/ImpactDatabase/Age.html

I believe that in the range of 1 to 0.1 million years should we we would find much more craters if in fact the SAO 128711 had released thousands of comets to the inner regions of the solar system.

To test this possibility I try simulate the close encounter of Gliese 710 in the U.S. To this I created an "Oort cloud" around the Sun with the ( inner and outer ) estimated distances for it , eliminated the planets and insert the Gliese 710 in the simulation with you real XYZ velocities to see if it really would have launch a swarm of comets to inside of the solar system.

I ran the simulation for about 10 million years, with a timestep of 6 years:

Few years after Gliese 710 collision:






Little more than a million years, note that most of the particles are ejected out of the solar system. Few have its orbit perturbed and migrate to a little beyond the inner Oort cloud limit but do not continue to enter the solar system:






With about 3 million years the particles ejected out of the solar system began to be attracted back:






With 9 million years of simulation many particles (those near the Oort Cloud) ejected out of the solar system return to the cloud. The particles ejected into the solar system have changed very little of their positions and did not enter the inner solar system:




Apparently the tangential passage of a star with the mass of Gliese 710 by the Oort cloud is not enough to eject a sufficient number of cometary bodies into the inner solar system put us at risk.

Although I do not know to evaluate the real accuracy of this simulation because the simulated Oort cloud does not have the density nor the actual configuration expected for the cloud, but I guess that these differences would not cause great variations in results.


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[Naru523]

Awesome.

[atomic7732]

The thing I think, is maybe if you made the Oort cloud wider, and ran maybe, say 5 simulations. Then compare results. 

[APODman]

The thing I think, is maybe if you made the Oort cloud wider,

Yes since the outer edge of the Oort cloud are more well definited than the inner, in my new simulations the Oort cloud varies its internal limit within acceptable parameters.

and ran maybe, say 5 simulations. Then compare results. 

I'm doing this a few days because each simulation takes about two days the trees day to complete.


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[Darvince]

I noticed that inaccuracies build up quickly even with a time-step labeled accurate. So particles might still manage to get within 50 AU.