Planet Detection Simulations for Several Possible TESS Extended Missions

TL;DR

This paper uses simulations to estimate exoplanet detection rates for potential TESS extended missions, showing sustained discovery potential and highlighting the importance of extended observations for future transit predictions.

Contribution

It provides the first detailed simulation-based analysis of exoplanet detection prospects for various possible TESS extended mission scenarios.

Findings

No sharp decline in planet detections in the third year.

Detection rates of sub-Neptune planets are relatively unaffected by pointing schedules.

Extended missions improve predictions of future transits and occultations.

Abstract

The Transiting Exoplanet Survey Satellite (TESS) will perform a two-year survey of nearly the entire sky, with the main goal of detecting exoplanets smaller than Neptune around bright and nearby stars. There do not appear to be any fundamental obstacles to continuing science operations for at least several years after the two-year Primary Mission. To provide a head start to those who will plan and propose for such a mission, we present simulations of exoplanet detections in a third year of TESS operations. Our goal is to provide a helpful reference for the exoplanet-related aspects of any Extended Mission, while recognizing this will be only one part of a larger community discussion of the scientific goals. We use Monte Carlo simulations to try and anticipate the quantities and types of planets that would be detected in each of 6 plausible scenarios for a one-year Extended Mission following the two-year Primary Mission. We find that: (1) there is no sharp fall-off in the planet discovery rate in the third year; (2) the quantity of newly detected sub-Neptune radius planets does not depend strongly on the schedule of pointings; (3) an important function of an Extended Mission would be improving our ability to predict the times of future transits and occultations of TESS-detected planets.