Which condition in a nebula would prevent nuclear fusion

this is not my work

-Brooks Nelson

Brooks Nelson, Chemist at University of Florida

Answered Oct 12, 2018 · Author has 368 answers and 54.1k answer views

My limited understanding is you need pressure, temperature and enough elements that can fuse. If the temperature and pressure aren't high enough and/or you don't have enough elements that can fuse, then no fusion.

In fact I've never heard of fusion in a nebula, only in a star. The exception being a brown dwarf, which is considered substellar at 10 to 90 Jupiters in mass, and they can fuse deuterium (if over 13J) and also lithium (if over 60 J). But the burn through all of it in about 10 million years and wouldn't emit light like a main sequence star would.

a core temperature of only ten thousand Kelvin

Explanation:

Plato/Edmentum

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .