Disentangling the hemispheres of Teegarden's Star b with LIFE

TL;DR

This study demonstrates that with three days of broadband observation, the LIFE instrument could distinguish hemispheres of Teegarden's Star b, aiding in understanding its climate and potential habitability.

Contribution

The paper introduces a method combining LIFEsim software and climate models to assess the observational capabilities of LIFE for Teegarden's Star b, highlighting its potential for spatial resolution.

Findings

3 days of observation can distinguish hemispheres at 1σ confidence

LIFE can potentially resolve surface features linked to water clouds

Fast-rotators in G-class star zones are harder to analyze

Abstract

Teegarden's Star is one of the most promising targets for the first observations of LIFE, as a non-transiting rocky planet with similar bulk properties to the Earth, and a relatively quiescent M-dwarf host star. We use LIFEsim, a software developed by the ETH LIFE team, along with thermal emission maps obtained from a suite of three-dimensional global climate model (GCM) simulations, to explore the sensitivity of LIFE to the observation geometry. We find that 3 days of observation in broadband would be enough to disentangle the hemispheres of the planet with a 1{\sigma} or 3{\sigma} confidence level with a baseline or optimistic scenario respectively. Doing the same for a fast-rotator in the habitable zone of a G-class star would be prohibitively challenging. Given enough observation time, the sensitivity of LIFE may allow some spatial resolution of Teegarden's Star b to be achieved, which may directly link to the presence of water clouds and therefore an active hydrology.