Characterizing the Galactic and Extragalactic Background Near Exoplanet Direct Imaging Targets

TL;DR

This study assesses the likelihood of background sources contaminating exoplanet imaging observations, using catalogs and simulations to inform target selection for space telescopes.

Contribution

It combines multiple catalogs and galaxy simulations to evaluate background source contamination risks for exoplanet imaging targets.

Findings

Low probability of background stars in most target fields.

Higher contamination risk at low galactic latitudes.

Faint stellar sources could impact observations at certain locations.

Abstract

As more missions attempt to directly image and characterize exoplanets orbiting nearby sun-like stars, advance characterization of possible contaminating background sources becomes more important and can impact target selection. This paper describes an exploration of the Hubble Source catalog, Gaia catalog and Besancon galaxy simulations in order to determine the likelihood of having a contaminating source in the background of a set of high proper motion stars in the expected timeframe of observations for the Nancy Grace Roman Space Telescope Coronagraphic Instrument. The analysis shows that for most of the targets, there is a very low possibility of a star falling within the CGI field of view, but that at low galactic latitudes where there is a greater density of sources, faint stellar background sources could be a concern.