DOI: 10.7910/dvn/tky3kc
title: Luhman 16AB IGRINS Spectral Atlas

description: This is the dataset reported by Ishikawa et al. (2025) "A 1.48–2.48 μm 𝑅=28 000 spectroscopic atlas of the L7.5 and T0.5 components of the nearest pair of brown dwarfs: Luhman 16AB". It includes the H- and K-band high-SNR high-dispersion spectra of Luhman 16AB (WISE J104915.57-531906.1AB) from IGRINS (Gemini South) and the Sonora Bobcat Alternative B model that best fits them. Estimated best-fit parameters and the results of radial velocity (RV) analysis are also included. If these data help your work, please cite Ishikawa et al. (2025).&lt;br&gt;
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All files are text files and the lines starting with "#" are header comments. The following is a brief description of each of the four directories:&lt;br&gt;
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&lt;h3&gt;1. fitted_models_and_spectra&lt;/h3&gt;
High-SNR IGRINS spectra of Luhman 16AB combined from all epochs, along with their uncertainties and the best-fit model spectra. Files are organised separately for each of the two components of Luhman 16A and B (L7.5, T0.5) and for each of the 46 echelle orders of IGRINS. This results in 2 × 46 = 92 individual files. &lt;br&gt;
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Each file contains the following four columns (with fluxes normalised by the mean of each order):&lt;br&gt;
&lt;pre&gt;&lt;code&gt;# wavelength (um),    data flux,      uncertainty,     model flux&lt;/code&gt;&lt;/pre&gt;
These are the data plotted in the second panel from the top in Figure B1 of APPENDIX B in Ishikawa et al. (2025).&lt;br&gt;
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&lt;h3&gt;2. all_combined_stitched_spectra_and_fitting_parameters&lt;/h3&gt;
This directory contains all the data plotted in Figures 6 and 7 of Ishikawa et al. (2025), including order-stitched spectra and best-fit atmospheric parameters for each order. Files beginning with "fig6_" are for Luhman 16A, whilst those beginning with "fig7_" are for Luhman 16B. The letter following "panel_" in the filename corresponds to the panel designations in Figures 6 and 7. &lt;br&gt;
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Panel a includes the spectra of each component combined from all epochs with all orders stitched together and their uncertainties. Panel b contains model spectra that incorporate only specific single molecules and collision-induced absorption (CIA). Panels c to i list the results of model fitting for each order (best-fit atmospheric parameters and the reduced chi-square goodness-of-fit statistic). For more details, please refer to Section 4.1 and the captions of Figures 6 and 7 in the paper.&lt;br&gt;
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For reference, the header rows of each file are provided below:&lt;br&gt;
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fig?_panel_a_flux.txt: &lt;br&gt;
&lt;pre&gt;&lt;code&gt;# Wavelengths (µm),      Normalized flux&lt;/code&gt;&lt;/pre&gt;
fig?_panel_a_uncertainty.txt:&lt;br&gt;
&lt;pre&gt;&lt;code&gt;# Wavelengths (µm),      Uncertainty&lt;/code&gt;&lt;/pre&gt;
fig?_panel_b_single_molecule_spectra.txt:&lt;br&gt;
&lt;pre&gt;&lt;code&gt;# Wavelengths (µm),      H2O (W/m^2/m),           CH4 (W/m^2/m),           CO (W/m^2/m),            NH3 (W/m^2/m),           FeH (W/m^2/m),           H2 (W/m^2/m),            H2S (W/m^2/m)&lt;/code&gt;&lt;/pre&gt;
fig?_panel_c_to_i_best_fit_parameters_in_each_order.txt:&lt;br&gt;
&lt;pre&gt;&lt;code&gt;# Mid-order λ (µm),      Teff,                    logg,                    fsed,                    Kzz,                     vsini,                   RV,                      Reduced chi-square&lt;/code&gt;&lt;/pre&gt;
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&lt;h3&gt;3. each_epoch_spectra&lt;/h3&gt;
This directory contains reduced spectra for each epoch. Data for each echelle order are stored in separate subdirectories. The directory names follow the pattern "ascii_[H or K]order[orderID]", where the orderID corresponds to the order number m in Ishikawa et al. (2025) according to the following formulae:&lt;br&gt;
        m = orderID + 98 for H band&lt;br&gt;
        m = orderID + 71 for K band&lt;br&gt;
For example, "ascii_Horder18/" contains data for order m = 116 and "ascii_Korder06/" for order m = 77.&lt;br&gt;
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Each file contains the following five columns:&lt;br&gt;
&lt;pre&gt;&lt;code&gt;# wav_both, flux_A, uncert_A, flux_B, uncert_B&lt;/code&gt;&lt;/pre&gt;
Please note that the wavelength array is shared because both binary components of Luhman 16 were observed simultaneously on the slit. &lt;br&gt;
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Each directory contains data files for each of the 93 epochs, plus a "fname.lst" file, which lists the file names in the directory in the order that the observations were taken. The mid-exposure times (Julian Day) for these epochs are recorded in "JDs.txt" in the same order. The corresponding barycentric velocity correction factors are in "BVCs.txt".&lt;br&gt;
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&lt;h3&gt;4. RV_data&lt;/h3&gt;
This directory contains all the RV analysis data plotted in Figure 24 of Ishikawa et al. (2025). Three RV files "RV_Luhman16A.txt", "RV_Luhman16B.txt", and "RV_Luhman16B_relative_to_A.txt" contain the RV values (km/s) for Luhman 16A, Luhman 16B, and Luhman 16B relative to Luhman 16A, respectively, for each of the 46 orders across all 93 epochs. "JD_and_CRX.txt" contains the mid-exposure time (JD) for each of the 93 epochs, along with the chromatic RV index (Zechmeister et al. 2018). "wav_mid_order.txt" contains the mid-order wavelength (µm) for each of the 46 orders. For more details, please refer to Section 5.1 and the caption of Figure 24 in the paper.&lt;br&gt;
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