# TESS observations of the asynchronous polar CD Ind: mapping the changing accretion geometry

## TL;DR

This study uses TESS data to monitor an asynchronous polar star, revealing dynamic changes in its magnetic accretion geometry over a beat cycle, supported by modeling and simulations.

## Contribution

It provides the first detailed optical mapping of accretion geometry changes in an asynchronous polar over its beat cycle using TESS data.

## Key findings

- Accretion geometry shifts from single to two poles and back.
- Cyclotron emission maps show changing accretion regions.
- Simulations support the observed accretion scenario.

## Abstract

We present the results of near continuous TESS optical observations of the asynchronous polar CD Ind (RX J2115-5840). The 27.9 d long light curve, with 2 min resolution, reveals remarkable changes in the magnetic accretion geometry of the system over the 7.3 d beat period. We have modelled the changes in the optical spin period pulse shape using a cyclotron emission mapping technique. The resulting cyclotron emission maps of the magnetic white dwarf reveal how the accretion geometry changes from single to two pole accretion and back over the beat cycle. Finally, we present the results from particle based numerical magnetic accretion simulations, that agree with our interpretation of the changing accretion scenario.