Molecular Abundances in the Atmosphere of the T Dwarf Gl 229B

摘要: We present new high-resolution infrared spectra of the T dwarf Gliese 229B in J, H, and K bandpasses. analyze each these as well previously published to determine its metallicity abundances NH3 CO terms surface gravity Gl 229B, which remains poorly constrained. The increases with increasing is below solar value unless a high-gravity brown log g (cgs) ≈ 5.5. abundance determined from both H- K-band spectra, probe two different levels atmosphere. find that data expected chemical equilibrium, we interpret strong evidence for dynamical transport This consistent previous detection provides additional constraints on dynamics atmosphere this dwarf.