Carbon dioxide and amorphous water ices in the debris disk around β Pictoris
Data files
Sep 08, 2026 version files 694.53 KB
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bestfit_model_AWI_params.csv
43.18 KB
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bestfit_model_AWI.csv
10.80 KB
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bestfit_model_AWICO2_params.csv
95.39 KB
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bestfit_model_AWICO2.csv
10.83 KB
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bestfit_model_AWICWICO2_params.csv
150.88 KB
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bestfit_model_AWICWICO2.csv
10.82 KB
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bestfit_model_CWI_params.csv
61.86 KB
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bestfit_model_CWI.csv
10.85 KB
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bestfit_model_CWICO2_params.csv
60.77 KB
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bestfit_model_CWICO2.csv
10.85 KB
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bestfit_model_H2OCO2101_params.csv
66.44 KB
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bestfit_model_H2OCO2101.csv
10.82 KB
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betaPictoris_NE.csv
34.34 KB
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betaPictoris_SW.csv
34.34 KB
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opticaldepth_NE.csv
75.41 KB
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README.md
6.96 KB
Abstract
The star β Pictoris is orbited by a dusty debris disk, within which planet formation is occurring. The disk extends far from the star such that molecules in the outer disk should freeze. We observed the β Pictoris disk in the near-infrared using the James Webb Space Telescope. The spectrum shows features due to amorphous water ice (<7% crystallinity), and carbon dioxide ice in both the 12CO2 and 13CO2 isotopologues. We infer that the CO2 ice is intimately mixed with the water ice, at a ratio of 1:10. This implies that the ices formed in cold conditions, likely in the interstellar medium during a phase of amorphous H2O- dominated formation. Frequent collisions within the debris disk are required to explain the observed uniform distribution of icy dust grains.
https://doi.org/10.5061/dryad.n8pk0p36d
Description of the data and file structure
Contact Information
Name: Sarah Betti
Institution: Space Telescope Science Institute
Email: sbetti@stsci.edu
Dataset Overview
This dataset contains the data required to replicate analysis and plots in Betti et al, (in review) which measures and characterizes ices in the debris disk around β Pictoris measured with JWST/NIRSpec IFU PRISM. The data covers the NE arms of the debris disk and has been fully reduced and spatially and spectrally extracted from the debris disk.
Description of the data and file structure
The files in this repository are tabular .csv files of the spectral extractions from 1-5 μm along with models of the ice and dust properties of the 3 μm water ice feature, including differential evolution corner plot information for the best fitting parameters from the model fitting.
Files and variables
File: bestfit_model_AWI.csv
Description: This files contains the best fit model to 3 μm water ice feature using a mixture of olivine, amorphous carbon, and amorphous water ice.
Variables
- microns: wavelength in microns
- scaled_opdepth: best fit scaled optical depth model
File: bestfit_model_AWI_params.csv
Description: This files contains the differential evolution parameter space explored to find the best fit models for the AWI model.
Variables
- amin: minimum grain size in microns
- aexp: grain size distribution exponent
- f_oli: volume fraction of olivine in grain mixture
- chi2: χ2 of the model to the data
File: bestfit_model_CWI.csv
Description: This files contains the best fit model to 3 μm water ice feature using a mixture of olivine, amorphous carbon, and crystalline water ice.
Variables
- microns: wavelength in microns
- scaled_opdepth: best fit scaled optical depth model
File: bestfit_model_CWI_params.csv
Description: This files contains the differential evolution parameter space explored to find the best fit models for the CWI model.
Variables
- amin: minimum grain size in microns
- aexp: grain size distribution exponent
- f_oli: volume fraction of olivine in grain mixture
- chi2: χ2 of the model to the data
File: bestfit_model_AWICO2.csv
Description: This files contains the best fit model to 3 μm water ice feature using a mixture of olivine, amorphous carbon, amorphous water ice, and CO2 ice.
Variables
- microns: wavelength in microns
- scaled_opdepth: best fit scaled optical depth model
File: bestfit_model_AWICO2_params.csv
Description: This files contains the differential evolution parameter space explored to find the best fit models for the AWI+CO2 model.
Variables
- amin: minimum grain size in microns
- aexp: grain size distribution exponent
- f_oli: volume fraction of olivine in grain mixture
- f_h2o: volume fraction of amorphous water ice in grain mixture
- chi2: χ2 of the model to the data
File: bestfit_model_CWICO2.csv
Description: This files contains the best fit model to 3 μm water ice feature using a mixture of olivine, amorphous carbon, crystalline water ice, and CO2 ice.
Variables
- microns: wavelength in microns
- scaled_opdepth: best fit scaled optical depth model
File: bestfit_model_CWICO2_params.csv
Description: This files contains the differential evolution parameter space explored to find the best fit models for the CWI+CO2 model.
Variables
- amin: minimum grain size in microns
- aexp: grain size distribution exponent
- f_oli: volume fraction of olivine in grain mixture
- f_h2o: volume fraction of crystalline water ice in grain mixture
- chi2: χ2 of the model to the data
File: bestfit_model_AWICWICO2.csv
Description: This files contains the best fit model to 3 μm water ice feature using a mixture of olivine, amorphous carbon, amorphous water ice, crystalline water ice, and CO2 ice.
Variables
- microns: wavelength in microns
- scaled_opdepth: best fit scaled optical depth model
File: bestfit_model_AWICWICO2_params.csv
Description: This files contains the differential evolution parameter space explored to find the best fit models for the AWI+CWI+CO2 model.
Variables
- amin: minimum grain size in microns
- aexp: grain size distribution exponent
- f_oli: volume fraction of olivine in grain mixture
- f_h2o: volume fraction of amorphous water ice in grain mixture
- f_co2: volume fraction of CO2 water ice in grain mixture
- chi2: χ2 of the model to the data
File: bestfit_model_H2OCO2101.csv
Description: This files contains the best fit model to 3 μm water ice feature using a mixture of olivine, amorphous carbon, amorphous water ice, and a H2O:CO2=10:1 mixture.
Variables
- microns: wavelength in microns
- scaled_opdepth: best fit scaled optical depth model
File: bestfit_model_H2OCO2101_params.csv
Description: This files contains the differential evolution parameter space explored to find the best fit models for the AWI+CWI+CO2 model.
Variables
- amin: minimum grain size in microns
- aexp: grain size distribution exponent
- f_oli: volume fraction of olivine in grain mixture
- chi2: χ2 of the model to the data
File: opticaldepth_NE.csv
Description: This files contains the optical depth of the NE spectral extraction from 2-5 μm.
Variables
- microns: wavelength in microns
- optical_depth: optical depth
- optical_depth_err: volume fraction of olivine in grain mixture
- chi2: χ2 of the model to the data
File: betaPictoris_NE.csv
Description: This file contain the reduced and normalized spectral extractions for the NE arm.
Variables
- wavelength (um): wavelength in microns
- normalized Fdisk/Fstar: second column is the reflectance spectrum normalized to 2.5 μm
- normalized Fdisk/Fstar err: error on the reflectance spectrum normalized to 2.5 μm
File: betaPictoris_SW.csv
Description: This file contain the reduced and normalized spectral extractions for the SW arm.
Variables
- wavelength (um): wavelength in microns
- normalized Fdisk/Fstar: second column is the reflectance spectrum normalized to 2.5 μm
- normalized Fdisk/Fstar err: error on the reflectance spectrum normalized to 2.5 μm
Code/software
All .csv files can be read using any spreadsheet or text editor (excel, etc) and can be read easily using python (numpy or pandas).
Access information
Other publicly accessible locations of the data:
- The raw and pipeline reduced data is found at https://mast.stsci.edu under proposal ID 1563.
This data was collected for the JWST/NIRSpec PRISM IFU. It has been processed through the JWST pipeline as well as an independent pipeline for spectral extraction.