EF Eridani in the low state

The polar EF Eridani (2A 0311-227) was once one of the brightest soft X-ray sources in the sky. For the past decade it has been in an extended inactive state (with the exception of occasional short "burps"). We seek to study the residual X-ray activity in this system. The data suggest that the residual optical activity occurs either on the irradiated surface of the substellar mass companion or in a coupling region where the secondary's wind and/or its magnetic field interacts with the megaGauss field of the white dwarf. X-ray observations will provide important clues to the magnetic geometry of polars, and the physics of the coupling region. This is a resubmission of an AO9 category C program.