so, you are referring about the smallest star, stars smaller than the sun and earth about 12,800 km across. absolutely, stars are very massive very huge, and different brightness , but we can see about a little size when viewed from earth, its because they are very far away from the earth, million thousand kilometers away distance, we can see about their apparent brightness, remember that there are no stars smallest than earth but based on my study, the smallest star discovered is
61 Cygni about the size of the sun its very far away from earth it can't be viewed by our naked eye you can use a telescope in order to see it.
