6 papers
JWST Observations of the Metal-poor T Dwarf WISEA J155349.96+693355.2: The First Brown Dwarf Associated with the Gaia-Enceladus Milky Way Substructure
Aaron M. Meisner, Adam J. Burgasser, Chih-Chun Hsu +15
We present JWST NIRSpec and MIRI observations of the metal-poor T dwarf WISEA J155349.96+693355.2. The combined NIRSpec/prism plus MIRI/LRS spectrum (R ~ 100) provides 0.6-12 m…
Time-resolved JWST Retrieval Analysis of the Coldest Brown Dwarf: Temperature and Chemical Variations in WISE 0855-07
Harshil Kothari, Caroline V. Morley, Brittany E. Miles +12
WISE J0855-07 is the coldest known brown dwarf (estimated Teff~250 K), offering a rare opportunity to probe atmospheric physics in the temperature and mass regime that overlaps dir…
Water Cloud and Chemical Modulations in the Coldest Brown Dwarf
Brittany E. Miles, James Mang, Caroline V. Morley +24
We present high signal-to-noise, medium resolution (R ~ 1000), time-series JWST/NIRSpec spectra of WISE 0855 (265K), the coldest known brown dwarf. Medium resolution, time-series s…
A Comprehensive Atmospheric Retrieval Analysis of 22 James Webb Space Telescope Spectral Energy Distributions of Cool Brown Dwarfs
Harshil Kothari, Michael C. Cushing, Samuel A. Beiler +5
We present a uniform atmospheric retrieval analysis of 22 late-T and Y-type brown dwarfs within 20 pc, observed with the James Webb Space Telescope NIRSpec PRISM and MIRI LRS. This…
A Tale of Two Molecules: The Underprediction of CO and Overprediction of PH in Late T and Y Dwarf Atmospheric Models
Samuel A. Beiler, Sagnick Mukherjee, Michael C. Cushing +5
The sensitivity and spectral coverage of JWST is enabling us to test our assumptions of ultracool dwarf atmospheric chemistry, especially with regards to the abundances of phosphin…
Probing the Heights and Depths of Y Dwarf Atmospheres: A Retrieval Analysis of the JWST Spectral Energy Distribution of WISE J035934.06540154.6
Harshil Kothari, Michael C. Cushing, Ben Burningham +5
We present an atmospheric retrieval analysis of the Y0 brown dwarf WISE J035934.06540154.6 using the low-resolution 0.96--12 m JWST spectrum presented in \citet{Beiler_2023}.…