Resynchronization of the Asynchronous Polar CD Ind

TL;DR

This study analyzes over 46,000 observations of the asynchronous polar CD Ind, estimating its resynchronization time to be approximately 6400 years, significantly longer than other known APs, and refines its orbital and spin periods.

Contribution

The paper provides the first detailed resynchronization time estimate for CD Ind, expanding understanding of APs' post-nova evolution and dynamics.

Findings

Resynchronization time of CD Ind is approximately 6400 years.

Orbital period is refined to 110.820 minutes.

White dwarf spin period is measured at 109.6564 minutes.

Abstract

CD Ind is one of only four confirmed asynchronous polars (APs). APs are strongly magnetic cataclysmic variables of the AM Herculis subclass with the characteristic that their white dwarfs rotate a few per cent out of synchronism with their binary orbit. Theory suggests that nova eruptions disrupt previously synchronized states. Following the eruption, the system is expected to rapidly resynchronize over a timescale of centuries. The other three asynchronous polars - V1432 Aql, BY Cam and V1500 Cyg - have resynchronization time estimates ranging from 100 to more than 3500 years, with all but one being less than 1200 years. We report on the analysis of over 46000 observations of CD Ind taken between 2007 and 2016, combined with previous observations from 1996, and estimate a CD Ind resynchronization time of 6400 +/- 800 years. We also estimate an orbital period of 110.820(1) minutes and a current (2016.4) white dwarf spin period of 109.6564(1) minutes.