FUOr diagnostics in the J band. On the left, a plot of H₂O 1.34 μm spectral index vs. Si I 1.32 μm EW, comparing a strong molecule with an atomic feature. The H₂O 1.34 μm signature (unity is no detectable H₂O) is more prominent at lower temperatures and is weakly dependent on surface gravity, being stronger in dwarfs than in lower gravity giants. FUOrs are strong in both H₂O 1.34 μm and Si I 1.32 μm absorption, and stand apart from M-type stars at all luminosities, as well as S-type sources (which may be poorly measured). On the right, a plot of Si I 1.32 μm vs. Al I 1.31 μm EWs, comparing two atomic features that are right next to one another in the spectra. The Al I 1.31 μm feature has a strong surface gravity dependence (being stronger in dwarfs than in giants) and grows in strength toward the coolest M-type temperatures. The Si I 1.32 μm feature is also stronger in dwarfs than in giants. Similar to the case of Si I 1.59 μm, FUOrs have generally stronger Si I 1.32 μm than either dwarfs or giants and weaker Al I 1.31 μm than M dwarfs, though they somewhat overlap with the M giants.