Final answer:
A star with a diameter of 10,000 miles is likely a white dwarf, a small, dense stellar remnant that is about the size of Earth.
Step-by-step explanation:
A star that is 10,000 miles in diameter is most likely a white dwarf. White dwarfs are stars that have exhausted their nuclear fuel and have collapsed to a very small size. A typical white dwarf, like the nearby star 40 Eridani B, is about the same size as Earth, which matches the size mentioned in the question. White dwarfs have a high density and are composed of degenerate matter, with their radius being only a small fraction of the Sun's despite having a considerable mass. Stars with diameters much larger than 10,000 miles are classified as red dwarfs, neutron stars, or supergiants, which are significantly larger than white dwarfs.