# High Spatial Resolution Thermal-Infrared Spectroscopy with ALES: Resolved Spectra of the Benchmark Brown Dwarf Binary HD 130948BC

## TL;DR

This study uses high-resolution thermal-infrared spectroscopy to analyze a brown dwarf binary, testing and refining evolutionary models by combining spectral data with system age and dynamical mass measurements.

## Contribution

It provides spatially-resolved L-band spectra of HD 130948BC, extending wavelength coverage and reconciling atmospheric parameters with evolutionary models to estimate a younger system age.

## Key findings

- Consistent atmospheric parameters support a younger system age (~0.50 Gyr).
- Spectroscopy extends into thermal infrared, improving model constraints.
- Addresses luminosity discrepancies in brown dwarf evolution models.

## Abstract

We present 2.9-4.1 micron integral field spectroscopy of the L4+L4 brown dwarf binary HD 130948BC, obtained with the Arizona Lenslets for Exoplanet Spectroscopy (ALES) mode of the Large Binocular Telescope Interferometer (LBTI). The HD 130948 system is a hierarchical triple system, in which the G2V primary is joined by two co-orbiting brown dwarfs. By combining the age of the system with the dynamical masses and luminosities of the substellar companions, we can test evolutionary models of cool brown dwarfs and extra-solar giant planets. Previous near-infrared studies suggest a disagreement between HD 130948BC luminosities and those derived from evolutionary models. We obtained spatially-resolved, low-resolution (R~20) L-band spectra of HD 130948B and C to extend the wavelength coverage into the thermal infrared. Jointly using JHK photometry and ALES L-band spectra for HD 130948BC, we derive atmospheric parameters that are consistent with parameters derived from evolutionary models. We leverage the consistency of these atmospheric quantities to favor a younger age (0.50 \pm 0.07 Gyr) of the system compared to the older age (0.79 \pm 0.22 Gyr) determined with gyrochronology in order to address the luminosity discrepancy.