Re: star vs planet
if we think it's big enough to burn it's on matter, but isn't doing so? What if it's doing so but only on a very limited basis and doesn't look like a star?
Re: small end of planet
How round is round? We have mountains, does that mean our gravity isn't stronger than our material? Does an asteroid of fine particles that assumes a round shape qualify as a planet?
I think on the small end they should set a specific mass. On the large end, it should not be burning it's own material and it should be orbiting something.
What do we call a planet that's not orbiting a star? Is it still a planet?
The only thing I learned that sticks in my head is: Stars twinkle, planets do not.
From the origin of the word, even more so.
Some small stars orbit a larger star or stars, and yet they are stars rather than planets. The currently closest star which isn't the Sun to Earth, Proxima is a small star orbiting two larger stars who have a sort of insular binary system between them.
As Jupiter currently does. It emits more radiation than it receives from the Sun. None of it is in visible wavelengths though. Is Jupiter therefore a star?