The eclipsing binary HS0705+6700 and the search for circumbinary objects

TL;DR

This paper studies the eclipsing binary HS0705+6700, analyzing transit time variations to investigate potential circumbinary objects, and discusses possible causes including additional bodies or magnetic effects.

Contribution

It provides new timing data supporting the presence of cyclical TTVs and explores potential explanations involving third or fourth bodies and magnetic effects.

Findings

TTVs support a cyclical pattern extending to 1.6 periods

Presence of additional bodies could explain TTVs

Magnetic dynamo effects remain possible explanations

Abstract

HS0705+6700 (also identified as V470 Cam) is a short period (2.3 h) post common envelope detached eclipsing sdB binary system which exhibits transit time variations (TTVs) of a cyclical nature. We report a further 25 timings of light minima and show that our new TTVs support and extend this cyclical pattern to 1.6 periods. We examine possible causes of the observed TTVs and confirm that the presence of a third, and possibly a fourth, body could provide an elegant explanation of these cyclical variations. However other non-circumbinary mechanisms, e.g. Applegate magnetic dynamo effects, will remain possible contenders until sufficient data has been accumulated to demonstrate that the periodicity of the TTVs is time independent.