Simulations of astrometric planet detection in Alpha Centauri by intensity interferometry

TL;DR

This paper evaluates the potential of ground-based intensity interferometry to detect Earth-like planets around Alpha Centauri by simulating a specialized observational setup and analyzing its astrometric precision.

Contribution

It introduces a simulation of a dedicated intensity interferometry system to assess its capability for detecting planetary perturbations in Alpha Centauri's orbit.

Findings

Astrometric error of ~0.5 mas from one night of observation

Error decreases with longer observations and multiple spectral channels

Detection of perturbations <10 microarcseconds is theoretically feasible

Abstract

Recent dynamical studies indicate that the possibility of an Earth-like planet around $\alpha\;$Cen A or B should be taken seriously. Such a planet, if it exists, would perturb the orbital astrometry by $<10 \ {\mu}\rm as$, which is $10^{-6}$ of the separation between the two stars. We assess the feasibility of detecting such perturbations using ground-based intensity interferometry. We simulate a dedicated setup consisting of four 40-cm telescopes equipped with photon counters and correlators with time resolution $0.1\,\rm ns$, and a sort of matched filter implemented through an aperture mask. The astrometric error from one night of observing $\alpha\;$Cen AB is $\approx0.5\,\rm mas$. The error decreases if longer observing times and multiple spectral channels are used, as $(\hbox{channels}\times\hbox{nights})^{-1/2}$.