Summer night world.
Here is a recycled answer of mine from here:
Endless global night.. but an agreeable climate, how come?
Brown dwarf emissions are almost all infrared. They do not put out much visible light and what they do is red.
Here are compared the emission spectra from 2 different brown dwarfs with that of the sun. Brown dwarfs are from
Sun is from wikipedia.
Note the brown dwarfs are in angstroms and the sun in nm. Divide angstroms by 10 to get nm.
Red light is 700 nm / 7000 A and almost all of the emission from the brown dwarfs are longer than that - invisible infrared.
Thus orbiting a brown dwarf you could get plenty of heat but very little light. This is your warm night world. The little bit of visible red light put out by the star makes the days red.
As regards the nuclear fire going out at 10 million years - true. But even though it does not shine, the brown dwarf stays hot and continues to radiate in the infrared. Your tidally locked planet is very close to its hot dwarf. It can stay warm and also "illuminated" by both the hot brown dwarf and also the dusty ring around the dwarf. That ring is hot too and secondarily emits infrared radiation for your planet.
The dark side of your planet will be colder. But maybe not that much colder - I could imagine the warm winds on the summer night world carry heat around the globe.
Seeing infrared is definitely possible. This world will look dark to us but not necessarily to its inhabitants.
/ a hypothetical scenario where the only life found in the galaxy around a brown dwarf is this species/
Galaxy? Those are big. Maybe you mean only intelligent life? I figure there must be some other form of life on their planet because they will get hungry otherwise. Some sort of autotroph?