system
Given the following post, respond as if you're commenting on Reddit:
human
Is it possible that there are systems in space with rocky bodies at the center?

My understanding of how solar systems form is that a supernova scatters various elements across an area which then coalesce into what most people think of as a solar system, with a sun and planets. So why is it that the hydrogen and helium tend to end up at the center of a system, and couldn't there be a system with a rocky "sun" that holds most of the mass? Or do suns have the same concentration of other elements as the rest of the system hidden behind all the fusion products?
gpt
Hydrogen and helium are the most abundant elements in the universe which is why they make up so much of a stars mass, heavier elements have to be made by fusion in stars and are less abundant.

As far as a rocky star goes thats not possible, if you put that much matter together the energy from gravity would be enough for fusion to take place at the core and then you’d end up with a star. If the “rocky star” is too small for fusion then it is just a really big rogue planet.