Bayesian Characterisation of Circumbinary Exoplanets with LISA

Abstract

The Laser Interferometer Space Antenna (LISA) will detect and characterize $\sim 10^4$ Galactic Binaries consisting predominantly of two White Dwarfs (WD). An interesting prospect within this population is a third object--another WD star, a Circumbinary Exoplanet (CBP), or a Brown Dwarf (BD)--in orbit about the inner WD pair. We present the first fully Bayesian detection and posterior analysis of sub-stellar objects with LISA, focusing on the characterization of CBPs. We used an optimistic astrophysically motivated catalogue of these CBP third-body sources, including their orbital eccentricity around the inner binary for the first time. We examined Bayesian Evidence computations for detectability, as well as the effects on the posterior distributions for both the inner binary parameters and the third-body parameters. We find that the posterior behavior bifurcates based on whether the third-body period is above or below half the observation time. Additionally, we find that undetectable third-body sources can bias the inner binary parameters whether or not the correct template is used. We used the information retrieved from the study of the CBP population to make an initial conservative prediction for the number of detectable BD systems in the original catalogue. We end with commentary on the predicted qualitative effects on LISA global fitting and Galactic Binary population analysis. The procedure used in this work is generic and can be directly applied to other astrophysical effects expected within the Galactic Binary population.

15 pages, 7 figures, 1 table

References in corpus (23)

• The NumPy array: a structure for efficient numerical computation
• Laser Interferometer Space Antenna
• Tertiary companions to close spectroscopic binaries
• The frequency of planetary debris around young white dwarfs
• A multiphysics and multiscale software environment for modeling astrophysical systems
• Population-Level Eccentricity Distributions of Imaged Exoplanets and Brown Dwarf Companions: Dynamical Evidence for Distinct Formation Channels
• Tests of Bayesian Model Selection Techniques for Gravitational Wave Astronomy
• Global Analysis of the Gravitational Wave Signal from Galactic Binaries
• Characterization of the stochastic signal originating from compact binaries populations as measured by LISA
• A Solution to the Galactic Foreground Problem for LISA
• Observationally driven Galactic double white dwarf population for LISA
• The effect of matter structure on the gravitational waveform
• Accreting Double white dwarf binaries: Implications for LISA
• The Canada-France Imaging Survey: Reconstructing the Milky Way Star Formation History from its White Dwarf Population
• Modelling the formation of double white dwarfs
• TDI-infinity: time-delay interferometry without delays
• Circumbinary exoplanets and brown dwarfs with the Laser Interferometer Space Antenna
• The Milky Way's bar structural properties from gravitational waves
• A statistical inference approach to time-delay interferometry for gravitational-wave detection
• Bayesian Time Delay Interferometry
• Golden galactic binaries for LISA: mass-transferring white dwarf black hole binaries
• Prospects for detecting exoplanets around double white dwarfs with LISA and Taiji
• Long-term stability of planets in and around binary stars

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