How do cold stars produce energy?

With only 7.5% of the sun’s mass, the coolest possible red dwarf star will still have a temperature of about 2,300 C, less than the melting point of carbon. However, if a star doesn’t have enough mass to ignite fusion, it becomes a brown dwarf, heated by the mechanical action of all that mass compressing inward. Average brown dwarfs will be about 1,700 C, which is still hot, but brown dwarfs can actually get more cooler.

A new class of these stars were discovered by that start at 300 degrees and go all the way down to about 27 degrees or room temperature. This means there are stars out there that anybody could touch. However, it's impossible for that to happen. Stars still have more than a dozen times the mass of Jupiter, and would tear a person's arm off with their intense gravity. They don’t have a solid surface. That’s about as cold as stars get.

Cold stars may seem like they have no chance of burning as bright as the other stars but they do get their energy from gravity. Their gravitational pulls may start out as not too strong but the more that it is able to get particle and gas from its area, the stronger and hotter the star is going to be.

Some people assume that cold stars are as cold as the cold that we experience on earth but this is not true. It just means that they are relatively colder than the other stars that are also found in the universe but they are still able to burn energy that is bright enough for their needs.