NICER observation list: Target ID 450901

SMC X-1 is thought to have a warped, precessing accretion disk (as evidenced by superorbital period modulations that range from 45-60 days). The superorbital period is projected to take a fourth excursion over the next 3 years, and over that time the superorbital period will change from ~60 days down to around 45 days. This implies that the accretion disk configuration is changing during this time. Previous work has well demonstrated that the shape of the soft pulse periods (i.e. the reprocessed emission) changes within a single 60 day cycle. This proposed program would use NICER to monitor the spectral shape and pulse profiles of SMC X-1 as the superorbital period takes a rare excursion and use this exceptional dataset to probe the physics of this warped, precessing accretion disk.