2018MNRAS.473.4692P

Polarimetry of IGR J1401-4306, a long-period (12.7 h) eclipsing intermediate polar and remnant of Nova Scorpii 1437 AD, reveals periodic variations of optical circular polarization, confirming the system as the longest-period eclipsing intermediate polar known. This makes it an interesting system from an evolutionary perspective. The circular polarization is interpreted as optical cyclotron emission from an accreting magnetic white dwarf primary. Based on the polarimetry, we propose that it is a disc-fed intermediate polar. The detection of predominantly negative circular polarization is consistent with only one of the magnetic poles dominating the polarized emission, while the other is mostly obscured by the accretion disc.