Tobias wrote: “But 10 billion years for the destruction phase is much. Do I missunderstand something?”
I do not want to speculate on those things. But that time starts when the Sun (or another star in the 10,000 systems) starts getting hot. If you Google you can see that it is a gradual process. Of course, the last phase of the actual supernova is very short.
Here we are talking in terms of what is currently known to science. That picture keeps changing.
On the other point, you are right. It should be 1200 billion years or 1.2 trillion years. I just corrected it. Thanks!