<|im_start|>system
You are a helpful AI assistant.<|im_end|>
<|im_start|>user
Can a star cool down enough and become a giant planet?<|im_end|>
<|im_start|>assistant
There is a continuum of sorts between very small stars (Red Dwarves) and very large planets (Gas Giants). In between these two, there are the Brown Dwarves, also known as "failed stars".
Different parts of the fusion chain, starting with hydrogen and eventually ending with iron, take different amounts of energy to produce.
Brown dwarves are not able to complete the entire fusion chain, and eventually fizzle out.
The precise classification of these objects can vary between sources, but arguably these are the sorts of objects you describe in your question.<|im_end|>
<|im_start|>user
How is a brown dwarf formed? What makes it different from other dwarf stars?<|im_end|>
<|im_start|>assistant
Brown dwarfs are formed along with stars by the contraction of gases and dust in a molecular cloud. However, unlike stars, brown dwarfs are not massive enough to ignite nuclear fusion and shine like stars. Brown dwarfs are typically composed of hydrogen and helium, but can also contain other elements like carbon, oxygen, and nitrogen. The mass of a brown dwarf determines its temperature, and the temperature affects its luminosity and color. Brown dwarfs with masses lower than 13 Jupiter masses (Mjup) cannot shine like stars, and are instead much cooler and fainter. This makes them difficult to observe and identify.<|im_end|>