The Observational Effects and Signatures of Tidally Distorted Solid Exoplanets

TL;DR

This paper investigates the potential for detecting tidal distortions in solid exoplanets, especially around small M class stars, and develops a simple model to identify observable signatures in their photometry.

Contribution

It introduces a new analytic expression to assess the detectability of tidal bulge signatures in the photometry of tidally distorted rocky exoplanets.

Findings

Tidal distortions can be significant for rocky exoplanets around small M class stars.

Detectable bulge signatures may appear in transit and ellipsoidal variation data.

The model helps identify systems where tidal effects are observationally detectable.

Abstract

Our work examines the detectability of tidally distorted solid exoplanets in synchronous rotation. Previous work has shown that tidally distorted shapes of close-in gas giants can give rise to radius underestimates and subsequently density overestimates for those planets. We examine the assumption that such an effect is too minimal for rocky exoplanets and find that for smaller M Class stars there may be an observationally significant tidal distortion effect at very close-in orbits. We quantify the effect for different stellar types and planetary properties using some basic assumptions. Finally, we develop a simple analytic expression to test if there are detectable bulge signatures in the photometry of a system. We find that close in for smaller M Class stars there may be an observationally significant signature that may manifest itself in both in-transit bulge signatures and ellipsoidal variations.