Detecting Gravitational Waves from Exoplanets Orbiting Binary Neutron Stars with B-DECIGO and DECIGO

TL;DR

This paper explores the potential of future space-based gravitational wave detectors like DECIGO to detect exoplanets orbiting binary neutron stars through frequency modulations in GW signals, expanding exoplanet discovery beyond traditional electromagnetic methods.

Contribution

It demonstrates that DECIGO can detect circumbinary exoplanets around binary neutron stars at cosmological distances, a novel application of GW astronomy for exoplanet detection.

Findings

DECIGO can detect exoplanets with masses dozens of times Jupiter's mass.

Detection is possible out to distances of about 1 Gpc, beyond the Local Supercluster.

Frequency modulations in GW signals can reveal the presence of orbiting exoplanets.

Abstract

The first detection of a gravitational-wave (GW) signal in 2015 has opened a new observational window to probe the universe. This probe can not only reveal previously inaccessible binaries, black holes, and other compact objects, but also can detect exoplanets through their imprint on GW signals, thereby significantly extend current exoplanet surveys. To date, nearly 6000 exoplanets have been confirmed, yet most of them reside either in the solar neighbourhood or along the sightline toward the Galactic bulge, reflecting the range limits of traditional electromagnetic techniques. In this work, we follow the method proposed in N.Tamanini&C.Danielski(2019) to investigate frequency modulations in GW signals from early-stage binary neutron stars (BNSs) induced by circumbinary planets (CBPs) and obtain that CBPs can be detected by the future space-borne detector DECi-hertz Interferometer Gravitational wave Observatory (DECIGO). For BNS system with the masses of two components both being 1.4 $M_{\odot}$, DECIGO could detect CBPs with mass being dozens of times that of Jupiter out to distances of $\sim 1$ Gpc, well beyond the Local Supercluster, offering an unprecedented opportunity to study planetary formation and evolution for the post main-sequence stage.