Multi-epoch time-resolved photometry of the eclipsing polar CSS081231:J071126+440405

TL;DR

This study presents a detailed five-year analysis of the eclipsing polar CSS081231, deriving orbital parameters, constraining potential circumbinary planets, and revealing complex accretion geometries and pole switching phenomena.

Contribution

It provides the first comprehensive, homogeneous dataset analysis of CSS081231, including a precise ephemeris and insights into accretion dynamics and possible planetary companions.

Findings

Eclipse duration of 433.08 seconds with high precision.

Orbital inclination between 79.3 and 83.7 degrees.

Constraints on circumbinary planet mass to <= 2 Jupiter masses.

Abstract

The eclipsing polar CSS081231 turned bright (V_max ~ 14.5) in late 2008 and was subsequently observed intensively with small and medium-sized telescopes. A homogeneous analysis of this comprehensive dataset comprising 109 eclipse epochs is presented and a linear ephemeris covering the five years of observations, about 24000 orbital cycles, is derived. Formally this sets rather tight constraints on the mass of a hypothetical circumbinary planet, M_pl <= 2 M_Jup. This preliminary result needs consolidation by long-term monitoring of the source. The eclipse lasts 433.08 +- 0.65 s, and the orbital inclination is found to be i=79.3 - 83.7 degrees. The centre of the bright phase displays accretion-rate dependent azimuthal shifts. No accretion geometry is found that explains all observational constraints, suggesting a complex accretion geometry with possible pole switches and a likely non-dipolar field geometry.