Program: GN-2017A-Q-13

We propose observing the profile of the He I 1.083-micron line in the colliding-wind Wolf-Rayet binary WR 140 at critical phases after periastron in order to measure the changes in the absorption to the wind-collision region and the emission sub-peak formed in the compressed wind flow. These spectra would complete the 2016B program that is monitoring the phases before and around periastron. In conjunction with other observations, the complete set of data will help locate the X-ray source relative to the stars, map the colliding wind flow and study the energy budget of the wind-collision process.