Brown dwarfs are celestial bodies in the gray area between planet and star.
They're huge, gaseous, hot compared to planets, and come in all different kinds.
(1) Is it possible for life to develop in the outer layers of such an object?
(2) If so, how large and/or complex could it get before being constrained by resources, heat etc.?
- Possible means able to happen at all. This is not to be confused with likely - I don't expect life to be common across brown dwarfs - but I want to know if it's realistic to even consider these circumstances happening once.
- Life means something that reproduces and evolves, that adapts to its environment, and that responds to stimuli. DNA is in no way necessary, nor are cells, to meet this criteria. Complexity is not a requirement to be "alive".
- To develop can include the creation of life by abiogenesis or the arrival of life through panspermia but either way it must not perish; it should be able to evolve and reproduce in its environment.
- A brown dwarf for this question is an object with > 13 $M_J$, so that deuterium fusion occurs comfortably. Its composition must occur naturally, and its volume and weather dynamics should be realistic, but you may determine other characteristics if it helps life develop. It may not orbit another object but it can have natural satellites if you so desire.
Related to but not a duplicate of Could a society exist within a brown dwarf which asks about humans settling within the atmosphere of such an object, as opposed to microorganisms evolving and growing complex, in that environment.