NICER observation list: Target ID 761401

We request 45 ks to monitor Cen X-3 over 3 orbits, probing orbital variability through spectro-timing analysis. With 3 observing runs, each having 10 snapshots (1.5 ks each) per orbit, we will measure changes in absorption/line fluxes. Previous reports hinted spectral differences even within the same orbital phase, beyond mass accretion rate variations in massive X-ray binaries. NICER's exceptional sensitivity, even < 3 keV, will enable detailed studies for the first time. As Cen X-3 is an eclipsing binary, we will also compare spectra during eclipse, out-of-eclipse, and during long, aperiodic dips to investigate the circumstellar region.The proposal is part of a large campaign for multi-wavelength/broadband observations of Cen X-3,coordinated with XRISM obs to enhance scientific insights.