STARS
Can a star turn into a planet?
Yes, a star can turn into a planet, but only for a particular type of star called a brown dwarf, and only if we use broad definitions of the words ‘star’ and ‘planet’. A brown dwarf is the lightest type of star, with a mass of about 13 to 80 times the mass of Jupiter. Such a star is too low in mass to trigger the nuclear fusion of regular hydrogen like in normal stars. Instead, it triggers the nuclear fusion of heavy hydrogen, which is much rarer. As a result, a brown dwarf glows like a normal star, but only dimly. Over time, a brown dwarf runs out of heavy hydrogen, cools and becomes dark. At this point, it can be considered a planet.