We propose to observe an exceptionally bright (H = 14.36, K = 14.36) and cool (Teff ∼ 830 K) T-type brown dwarf, Gl 229B, using Subaru/IRD and IRCS for a detailed spectrum analysis across four near-infrared bands (Y, J, H, K). With a high-precision (S/N >∼ 30), high-dispersion approach for such a best target among cool (Teff <∼ 1,000 K) sub-dwarfs, we will 1) obtain high precision, high-dispersion spectra across a broad wavelength range for the ideal target Gl 229B to better understand cool atmospheres, 2) use a combination of high-dispersion spectra from Subaru/IRD & IRCS and medium-dispersion spectra from JWST/NIRSpec & MIRI to accurately ever determine the atmospheric temperature structure and chemistry of this benchmark object, and 3) establish molecular absorption line lists in collaboration with experimental studies, tailored for the temperature region relevant to exoplanets and brown dwarfs. We request a total of three nights: one for IRD observation and two for IRCS observations in the K−- and K+-bands to fully cover the K-band. We expect to achieve the S/N of ∼ 50 in the IRD/YJ-bands, ∼ 68 in the IRD/H band, and ∼ 30 in the IRCS/K-band.
This document was translated from LATEX by HEVEA.