NICER observation list: Target ID 262601

Colliding wind binaries are unique laboratories to study of the behavior of shocked plasmas. In eccentric binaries, these conditions predictably vary with orbital phase and stellar separation, which allows sensitive tests as shock conditions change. The best example of a colliding wind binary shock laboratory is WR 140, a long-period, highly eccentric massive evolved binary in which wind-wind interactions generate variable emission from the X-ray to radio bands. We propose weekly monitoring of WR 140 with NICER through Cycle 1 to understand the changes in the shock as it recovers from the most recent periastron passage in December 2016 as the stars head toward apastron.