SPHEREx spectra of 37 field brown dwarfs show atmospheric models struggle with J/H/K peaks and 4um window especially at L/T transition, with data preferring weak-mixing Elf Owl models.
Ammonia as a tracer of chemical equilibrium in the T7.5 dwarf Gliese 570D
1 Pith paper cite this work. Polarity classification is still indexing.
1
Pith paper citing it
abstract
We present the first analysis of an optical to mid-infrared spectrum of the T7.5 dwarf Gliese 570D with model atmospheres, synthetic spectra, and brown dwarf evolution sequences. We obtain precise values for the basic parameters of Gl 570D: Teff=800 - 820K, log g (cm/s^2)=5.09 - 5.23, and log L/Lsun= -5.525 to -5.551. The Spitzer IRS spectrum shows prominent features of ammonia (NH3) that can only be fitted by reducing the abundance of NH3 by about one order of magnitude from the value obtained with chemical equilibrium models. We model departures from chemical equilibrium in the atmosphere of Gl 570D by considering the kinetics of nitrogen and carbon chemistry in the presence of vertical mixing. The resulting model spectrum reproduces the data very well.
fields
astro-ph.SR 1years
2026 1verdicts
ACCEPT 1representative citing papers
citing papers explorer
-
SPHEREx 0.75 to 5 $\mu$m Spectra for a Sequence of Nearby Brown Dwarfs
SPHEREx spectra of 37 field brown dwarfs show atmospheric models struggle with J/H/K peaks and 4um window especially at L/T transition, with data preferring weak-mixing Elf Owl models.