Uniform Forward-modeling Analysis of Ultracool Dwarfs. IV. Benchmarking the Sonora Diamondback and D. Saumon & M. S. Marley (2008) Atmospheric Models Across Late M, L, and T Types with Low-resolution 0.8–2.5 μ m Spectroscopy
Abstract
Abstract We present a systematic assessment of two major cloudy atmospheric model grids— SM08 and Sonora Diamondback —when applied to low-resolution, near-infrared (0.8–2.5 μ m) spectroscopy. Our analysis focuses on a uniform sample of 142 age-benchmark brown dwarfs and planetary-mass objects spanning late M, L, and T spectral types, with independently determined ages from 10 Myr to 10 Gyr. We perform forward-model spectral fitting for all benchmarks’ Infrared Telescope Facility/SpeX spectra ( R ∼ 80–250) using both SM08 and Sonora Diamondback atmospheric models to infer effective temperatures, surface gravities, metallicities, radii, and cloud sedimentation efficiencies. The two model grids yield broadly consistent results. Among L4–L9 dwarfs, we identify a statistically significant, population-level age dependence of the cloud parameter f sed , with young benchmarks (
Fields of Study & Subjects
Stellar
planetary
and galactic studies
Astronomy and Astrophysical Research
Astrophysics and Star Formation Studies
Publication details
- Journal / source
- The Astronomical Journal
- Publisher
- American Astronomical Society
- Volume
- 171
- Issue
- 3
- Pages
- 198–198
- Publication date
- 2 March 2026
- Language
- EN