Short Duration Accretion States of Polars as seen in TESS and ZTF data

TL;DR

This paper reports on the detection of very short brightness states in Polars using TESS and ZTF data, suggesting these states are common and can be explained by star spot migration interacting with the white dwarf's magnetic field.

Contribution

It introduces the observation of the shortest duration states in Polars and generalizes the star spot migration model to explain these phenomena.

Findings

Short duration states are common in Polars.

Star spot migration model explains both high and low states.

Magnetic interaction influences brightness states.

Abstract

Polars are highly magnetic cataclysmic variables which have been long observed to have both high and low brightness states. The duration of these states has been previously seen to vary from a number of days up to years. Despite this; these states and their physical origin has not been explained in a consistent manner. We present observations of the shortest duration states of a number of Polars observed by ZTF and TESS. This has allowed us to determine that short duration states are a relatively common feature across the population of Polars. Furthermore we have been able to generalise the model of star spot migration to explain both short lived high and low states in Polars by incorporating the interaction between the magnetic field of the white dwarf and that of the star spots.