Modeling TESS Objects of Interest to Characterize and Vet Planet Candidates

Exoplanets, planets beyond our solar system, are primarily discovered by NASA’s space-based TESS missions, which monitor the brightness of hundreds of thousands of stars. When a planet passes in front of its star from our point of view, it causes a ≲1% dip in the star’s brightness, producing what’s called a transit. These transits allow us to estimate the planet’s size, orbit, and even temperature. Currently, TESS has identified over 7,000 of these planet candidates, but not all of them are confirmed to be real planets. Many current models assume circular orbits, which may bias the planetary temperature, the planet's evolution, and even how common such planets are. We analyzed some of the most extreme planet candidates, including those with the highest and lowest temperatures, the largest and smallest sizes, the fastest orbits, and planets that most closely resemble Earth. We also examine planets orbiting stars that are unusually bright or have unusually high amounts of heavy elements (metallicity). We combined the transit data with physics-based models of stars, measurements of starlight across multiple wavelengths, and precise distance measurements from ESA’s Gaia mission. These models allow us to estimate both star and planet properties together in a self-consistent way. By analyzing these extreme systems carefully, we aim to confirm which candidates are real planets, better understand their unique properties, and gain insight into the bounds of possible planet formation. This effort improves the accuracy of planet classification and sheds light on just how diverse planets in our galaxy can be.