Completeness of Imaging Surveys for Eccentric Exoplanets

TL;DR

This paper analyzes how the eccentricity of exoplanets affects their detectability in direct imaging surveys, revealing that many planets may remain undetected due to their orbital positions.

Contribution

It introduces a method to quantify the detectable portion of eccentric exoplanet orbits based on survey parameters, highlighting potential observational biases.

Findings

A significant fraction of eccentric exoplanets are likely undetected in current surveys.

Detectability depends strongly on orbital parameters such as semi-major axis and eccentricity.

Many planets may be hidden due to their position in the orbit relative to the detection threshold.

Abstract

The detection of exoplanets through direct imaging has produced numerous new positive identifications in recent years. The technique is biased towards planets at wide separations due to the difficulty in removing the stellar signature at small angular separations. Planets in eccentric orbits will thus move in and out of the detectable region around a star as a function of time. Here we use the known diversity of orbital eccentricities to determine the range of orbits which may lie beneath the detection threshold of current surveys. We quantify the percentage of the orbit which yields a detectable signature as a function of semi-major axis, eccentricity, and orbital inclination and estimate the fraction of planets which likely remain hidden by the flux of the host star.