Large Interferometer For Exoplanets (LIFE): II. Signal simulation, signal extraction and fundamental exoplanet parameters from single epoch observations

TL;DR

This paper introduces LIFEsim, a simulation tool for space-based mid-infrared nulling interferometers, enabling the assessment of exoplanet detection and characterization capabilities, including signal extraction accuracy and parameter estimation.

Contribution

The paper presents LIFEsim, a novel simulation software that models exoplanet observations with a space-based MIR interferometer, incorporating noise sources and enabling performance evaluation.

Findings

Photon-noise dominated SNRs in simulations

Effective temperature estimated within 10% uncertainty

Exoplanet radius and separation uncertainties within 20% and 2% respectively

Abstract

The Large Interferometer For Exoplanets (LIFE) initiative is developing the science and a technology roadmap for an ambitious space mission featuring a space-based mid-infrared (MIR) nulling interferometer in order to detect the thermal emission of hundreds of exoplanets and characterize their atmospheres. In order to quantify the science potential of such a mission, in particular in the context of technical trade-offs, an instrument simulator is required. In addition, signal extraction algorithms are needed to verify that exoplanet properties (e.g., angular separation, spectral flux) contained in simulated exoplanet datasets can be accurately retrieved. We present LIFEsim, a software tool developed for simulating observations of exoplanetary systems with an MIR space-based nulling interferometer. It includes astrophysical noise sources (i.e., stellar leakage and thermal emission from local zodiacal and exo-zodiacal dust) and offers the flexibility to include instrumental noise terms in the future. LIFEsim provides an accessible way for predicting the expected SNR of future observations as a function of various key instrument and target parameters. The SNRs of the extracted spectra are photon-noise dominated, as expected from our current simulations. From single epoch observations in our mock survey of small ($R < 1.5 R_\mathrm{Earth}$) planets orbiting within the habitable zones of their stars, we find that typical uncertainties in the estimated effective temperature of the exoplanets are $\lesssim$10%, for the exoplanet radius $\lesssim$20%, and for the separation from the host star $\lesssim$2%. SNR values obtained in the signal extraction process deviate less than 10% from purely photon-counting statistics based SNRs. (abridged)