The Ariel Target List: The Impact of TESS and the Potential for Characterizing Multiple Planets within a System

Abstract

The ESA Ariel mission has been adopted for launch in 2029 and will conduct a survey of around 1000 exoplanetary atmospheres during its primary mission life. By providing homogeneous data sets with a high signal-to-noise ratio and wide wavelength coverage, Ariel will unveil the atmospheric demographics of these faraway worlds, helping to constrain planet formation and evolution processes on a galactic scale. Ariel seeks to undertake a statistical survey of a diverse population of planets; therefore, the sample of planets from which this selection can be made is of the utmost importance. While many suitable targets have already been found, hundreds more will be discovered before the mission is operational. Previous studies have used predictions of exoplanet detections to forecast the available planet population by the launch date of Ariel, with the most recent noting that the Transiting Exoplanet Survey Satellite (TESS) alone should provide over 1000 potential targets. In this work, we consider the planet candidates found to date by TESS to show that, with the addition of already confirmed planets, Ariel will already have a more than sufficient sample to choose its target list from once these candidates are validated. We showcase the breadth of this population, as well as exploring, for the first time, the ability of Ariel to characterize multiple planets within a single system. Comparative planetology of worlds orbiting the same star, as well as across the wider population, will undoubtedly revolutionize our understanding of planet formation and evolution.

A super-Earth and a mini-Neptune near the 2:1 MMR straddling the radius valley around the nearby mid-M dwarf TOI-2096

“…However, the ESA Ariel mission will observe ∼1000 exoplanets during its 4-yr prime mission, conducting a chemical survey of exoplanetary atmospheres (Tinetti et al 2018(Tinetti et al , 2021. Launching in 2029, many of the planets observed by the mission are expected to be found by TESS (Edwards & Tinetti 2022) and a diverse selection of targets will be observed to search for trends in atmospheric chemistry.…”

“…In the context of Ariel, we find that TOI-2096 b and c are no longer the best-in-class as, unlike JWST, the mission can cover a wide spectral coverage (0.5-7.8 µm) for bright stars. Nevertheless, the parameter space in which TOI-2096 b and c lie is sparsely populated and so they could still be observed by the mission, especially if, during the target selection, emphasis is placed upon studying smaller planets or multiple planets within a single system (Edwards et al 2019;Edwards & Tinetti 2022). by combining photometry from six TESS sectors and several ground-based facilities, high-resolution imaging, and spectral analysis.…”

Twinkle: a small satellite spectroscopy mission for the next phase of exoplanet science

“…The results of the Twinkle exoplanet survey will be highly valuable for informing the Ariel target selection and thus increasing the overall science yield of the mission. 12,13,43 Additionally, Twinkle's low resolution spectroscopy from space will complement the high resolution spectroscopy being conducted from the ground. [44][45][46][47] Figure 6.…”

ExoClock Project. III. 450 New Exoplanet Ephemerides from Ground and Space Observations

“…These resources consist of data from the literature, data obtained by telescopes from the ground, and finally data from space telescopes. The ExoClock project (Kokori et al 2021(Kokori et al , 2022) is an open, integrated platform, with the aim of continuously monitoring the ephemerides of the Ariel candidate targets (Edwards & Tinetti 2022). The organization of the project is thoroughly described in Kokori et al (2021), and the first largescale catalog of updated ephemerides for 180 planets was produced in Kokori et al (2022), by combining observations from ground-based telescopes and the literature.…”