Polarimetry of IGR J1401 - 4306 , a long period ( 12.7 hours ) , eclipsing intermediate polar and remnant of Nova Scorpii 1437 A.D. , 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 .