Gravitational Waves From Ultra Short Period Exoplanets

TL;DR

This paper explores the potential of gravitational wave detection, especially via LISA, to identify ultra short period exoplanets with periods less than 80 minutes, offering a new observational method.

Contribution

It demonstrates that gravitational waves from ultra short period exoplanets are detectable and could be used to discover such planets, a novel approach in exoplanet research.

Findings

Gravitational luminosity of these exoplanets is around 10^{30} erg/s.

Strain of gravitational waves is approximately 10^{-22}.

Frequencies are above 10^{-4} Hz, within LISA's sensitivity.

Abstract

In the last two decades, thousands of extrasolar planets were discovered based on different observational techniques, and their number must increase substantially in virtue of the ongoing and near-future approved missions and facilities. It is shown that interesting signatures of binary systems from nearby exoplanets and their parent stars can also be obtained measuring the pattern of gravitational waves that will be made available by the new generation of detectors including the space-based LISA (Laser Interferometer Space Antenna) observatory. As an example, a subset of exoplanets with extremely short periods (less than 80 min) is discussed. All of them have gravitational luminosity, $L_{GW} \sim 10^{30}$ $erg/s$, strain $h \sim 10^{-22}$, frequencies $f_{gw} > 10^{-4}$Hz, and, as such, are within the standard sensitivity curve of LISA. Our analysis suggests that the emitted gravitational wave pattern may also provide an efficient tool to discover ultra short period exoplanets.