Predicting the Yield of Potential Venus Analogs from TESS and their Potential for Atmospheric Characterization

TL;DR

This study estimates the number of Venus-like exoplanets TESS might discover and evaluates their potential for atmospheric characterization with JWST, focusing on planets within the Venus Zone and their observability.

Contribution

It provides the first detailed estimate of Venus analogs from TESS data and assesses their suitability for atmospheric studies with JWST.

Findings

Estimated 259 Venus analogs from TESS yield predictions.

46 Venus analogs identified in the TESS TOI list for sectors 1-13.

Venus analogs with radii < 1.5 R_⊕ have S/N > 40 for JWST observations.

Abstract

The transit method is biased toward short orbital period planets that are interior to their host star's Habitable Zone (HZ). These planets are particularly interesting from the perspective of exploring runaway greenhouse scenarios and the possibility of potential Venus analogs. Here, we conduct an analysis of predicted TESS planet yield estimates produced by Huang et al. (2018), as well as the TESS Object of Interest (TOI) list resulting from the observations of sectors 1 - 13 during Cycle 1 of the TESS primary mission. In our analysis we consider potential terrestrial planets that lie within their host star's Venus Zone (Kane et al. 2014). These requirements are then applied to a predicted planetary yield from the TESS primary mission (Huang et al. 2018) and the TOI list, which results in an estimated 259 Venus analogs by the end of the TESS primary mission, and 46 Venus analogs in the TOI list for sectors 1 - 13. We also calculate the estimated transmission spectroscopy signal-to-noise ratio (S/N) for Venus analogs from the predicted yield and TOI list if they were to be observed by the Near-Infrared Imager and Slitless Spectrograph (NIRISS) on the James Webb Space Telescope (JWST), as well as update the S/N cutoff values determined by Kempton et al. (2018). Our findings show that the best estimated Venus analogs and TOI Venus analogs with $R_{p} < 1.5 \, R_\odot$ have an estimated transmission spectroscopy S/N $> 40$ while planets with radii $2 \, R_\oplus < R_p < 4 \, R_\oplus$ can achieve S/N $> 100$