Stellar wobble in triple star systems

TL;DR

This paper reviews how the gravitational effects of nearby binary star systems can mimic planetary signals in radial velocity measurements, emphasizing the importance of distinguishing between true planets and binary-induced wobble.

Contribution

It summarizes previous modeling of binary effects on stellar radial velocity and discusses practical methods to differentiate between planetary signals and binary-induced wobble.

Findings

Binary systems can produce radial velocity signals similar to planets.

Unresolved faint binaries may lead to false planetary detections.

Strategies exist to distinguish binary effects from true planetary signals.

Abstract

The radial velocity method for detecting extra-solar planets relies on measuring the star's wobble around the system's center of mass. Since this is an indirect method, we may ask if there are other dynamical effects that can mimic such wobble. In recent articles\cite{1,2,3}, we modeled the effect of a nearby binary system on a star's radial velocity. We showed that, if we are unaware of this nearby binary, for instance because one component is unresolved or both components are faint stars, the binary's effect may mimic a planet. Here, we review this work, explaining in which circumstances the binary's effect may mimic a planet and we discuss what can be done in practice in order to distinguish between these two scenarios (planet or nearby binary).