A Grid of Contribution Functions to Help the Interpretation of Time-resolved Observations of Brown Dwarfs
Abstract
We present a grid of thermal emission contribution functions and their corresponding atmospheric spectra model for cloudy and cloud-free brown dwarfs, spanning effective temperatures Teff ∈ [500, 2000] K, surface gravities log g = [3.5, 5.5] [cgs], sedimentation efficiencies fsed = 1, 2, 3, 4 and 8, and eddy diffusion coefficients log Kzz = [6, 11]. We use temperature-pressure profiles from the Sonora Diamondback models in conjunction with the picaso radiative transfer code and the cloud modeling code virga, to explore how different atmospheric parameters influence the vertical distribution of emitted radiation for atmospheres in chemical equilibrium. We confirm that cloud opacity significantly impacts atmospheric emission depth in prominent molecular features such as CH4, H2O, CO, NH3, CO2, and atomic features Na and K. The atmospheric emission depth varies most notably in the J-band, and at mid-resolution spectra in the Na and K doublets. Our analysis highlights pressure-wavelength differences between cloudy and cloud-free atmospheres for characterizing L, L/T transition, and T-type brown dwarfs and demonstrates how contribution functions can guide targeted spectroscopic investigations. To facilitate observational planning, we provide an accessible database and web-based application that enable the community to compare observational data with our model grid of spectra and contribution functions with a wavelength range of 0.5 - 30 μm.
Versions
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BibTeX
@misc{phillippe2026grid,
title = {{A Grid of Contribution Functions to Help the Interpretation of Time-resolved Observations of Brown Dwarfs}},
author = {Myrla Phillippe and Theodora Karalidi and Elena Manjavacas and Natalia Oliveros-Gomez and Daniel Apai and Jonathan Fernandez and Kieran M. Manjrawala},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.19339},
eprint = {2609.19339},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.19339},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A Grid of Contribution Functions to Help the Interpretation of Time-resolved Observations of Brown Dwarfs
AU - Myrla Phillippe
AU - Theodora Karalidi
AU - Elena Manjavacas
AU - Natalia Oliveros-Gomez
AU - Daniel Apai
AU - Jonathan Fernandez
AU - Kieran M. Manjrawala
PY - 2026
DA - 2026/09/16
PB - arXiv
DO - 10.48550/arxiv.2609.19339
UR - https://arxiv.org/abs/2609.19339
AB - We present a grid of thermal emission contribution functions and their corresponding atmospheric spectra model for cloudy and cloud-free brown dwarfs, spanning effective temperatures T_eff ∈ [500, 2000] K, surface gravities log g = [3.5, 5.5] [cgs], sedimentation efficiencies f_sed = 1, 2, 3, 4 and 8, and eddy diffusion coefficients log K_zz = [6, 11]. We use temperature-pressure profiles from the Sonora Diamondback models in conjunction with the picaso radiative transfer code and the cloud modeling code virga, to explore how different atmospheric parameters influence the vertical distribution of emitted radiation for atmospheres in chemical equilibrium. We confirm that cloud opacity significantly impacts atmospheric emission depth in prominent molecular features such as CH_4, H_2O, CO, NH_3, CO_2, and atomic features Na and K. The atmospheric emission depth varies most notably in the J-band, and at mid-resolution spectra in the Na and K doublets. Our analysis highlights pressure-wavelength differences between cloudy and cloud-free atmospheres for characterizing L, L/T transition, and T-type brown dwarfs and demonstrates how contribution functions can guide targeted spectroscopic investigations. To facilitate observational planning, we provide an accessible database and web-based application that enable the community to compare observational data with our model grid of spectra and contribution functions with a wavelength range of 0.5 - 30 μm.
ER -