Final answer:
Red dwarfs are stars with low temperature and low luminosity. They are smaller and more compact than stars like the Sun.
Step-by-step explanation:
A star that has a low temperature and a low luminosity is a red dwarf. Red dwarfs are smaller and more compact than stars like the Sun, with a much lower surface temperature. An example of a red dwarf is Ross 614B, which has a surface temperature of 2700 K and only 1/2000 of the Sun's luminosity. These stars are called dwarfs because they have a diameter only 1/10 that of the Sun.