Finally, I am well aware that the value of the gravitational constant 𝐺 is 6.67408×10−11 and not 0.5, as I have implemented it here; using the correct value of 𝐺 results in a simulation that runs far too slow to appreciate.
It is strange to me that you chose to change the gravitational constant rather than simply choosing a different time step; can you ...
In your description you mention the gravitational constant is 0.5 for performance reasons, in the code it is actually 0.1.
There are times when the this pointer is necessary, but it is not necessary in the code under review (EntryPoint.cs, Body.cs and BodySystem.cs).
To some extent this is personal ...