Protosolar D-to-H abundance and one part-per-billion PH${}_3$ in the coldest brown dwarf

Melanie J. Rowland, Caroline V. Morley, Brittany E. Miles +24

The coldest Y spectral type brown dwarfs are similar in mass and temperature to cool and warm ($\sim$200 -- 400 K) giant exoplanets. We can therefore use their atmospheres as proxi…