Spectroscopic identification of habitable extra-solar planets

TL;DR

This paper introduces a Fourier spectroscopy method in the infrared to detect bio-signature spectral lines from Earth-like exoplanets, demonstrating its feasibility through simulations and laboratory experiments.

Contribution

It proposes a novel Fourier spectroscopy technique focusing on off-center interferogram parts to enhance sensitivity to planetary spectral features.

Findings

Feasible at a luminosity ratio of 10^-6 for Sun-like stars.

Numerical simulations support the method's effectiveness.

Laboratory experiments illustrate the method's practical application.

Abstract

An Earth-like extra-solar planet emits light which is many orders of magnitude fainter than that of the parent star. We propose a method of identifying bio-signature spectral lines in light from known extra-solar planets based on Fourier spectroscopy in the infra-red, using an off-center part of a Fourier interferogram only. This results in superior sensitivity to narrower molecular-type spectral bands, which are expected in the planet spectrum but are absent in the parent star. We support this idea by numerical simulations which include photon and thermal noise, and show it to be feasible at a luminosity ratio of 10^-6 for a Sun-like parent star in the infra-red. We also carried out a laboratory experiment to illustrate the method. The results suggest that this method should be applicable to real planet searches.