What is the old cold star?

Answer 1

An old cold star, often referred to as a "brown dwarf," is a celestial object that is too massive to be classified as a planet but not massive enough to sustain hydrogen fusion like true stars. Brown dwarfs typically have masses ranging from about 13 to 80 times that of Jupiter. They emit minimal light and heat, primarily through the residual energy from their formation, making them difficult to detect. As they age, they cool down and can become very faint, often appearing as "cold" stars in the universe.