The 2018 perihelion passage of comet 46P/Wirtanen afforded an opportunity to measure the abundances and spatial distributions of coma volatiles in a Jupiter-family comet with exceptional spatial resolution for several weeks surrounding its closest approach to Earth (Δ_min ∼0.078 au on UT December 16). We conducted near-infrared spectroscopic observations of 46P/Wirtanen using iSHELL at the NASA Infrared Telescope Facility on UT 2018 December 18 in direct coordination with observations using the newly upgraded NIRSPEC-2 instrument at the W. M. Keck Observatory, and securely detected fluorescent emission from CH₃OH, C₂H₆, and H₂O. This coordinated campaign utilizing the two premier near-infrared facilities in the northern hemisphere enabled us to sample distinct projections of the coma into the plane of the sky simultaneously, and provided an unprecedented view into the inner coma of 46P/Wirtanen near closest approach. We report rotational temperatures, production rates, and abundance ratios (i.e., mixing ratios) for all sampled species and compare our iSHELL results to simultaneous (or near-simultaneous) measurements taken with NIRSPEC-2. We demonstrate the extraordinary synergy of coordinated measurements using iSHELL and NIRSPEC-2, and advocate for future cometary studies that jointly leverage the capabilities of these two facilities.

彗星46P的2018近日点/ Wirtanen提供测量与出色的空间分辨率在木星族彗星的丰度和昏迷挥发的空间分布为围绕其最接近地球的方法（数周的机会Δ_分钟~0.078 AU UT上月16）。我们在直接协调进行使用ISHELL在NASA红外望远镜46P / Wirtanen的近红外光谱观测上UT 2018 12月18日，使用在WM凯克天文台新升级NIRSPEC-2仪器观察，并安全地从CH检测到的荧光发射₃ OH，C ₂ H ^ ₆，和H ₂O.利用两个主要的近红外设备在北半球这种协调的运动，使我们能够在昏迷的不同预测同时采样而起的飞机，并提供了一个前所未有的视图46P / Wirtanen附近最接近内昏迷。我们所有抽样物种报告旋转温度，生产速度，和丰度比（即混合比率）和我们的ISHELL比较结果与NIRSPEC-2拍摄的同时（或几乎同时）测量。我们演示使用ISHELL和NIRSPEC-2协调的测量，为今后彗星的研究，共同利用这两个设施的能力非凡的协同作用，并提倡。