TOI-2133b: A Sub-Neptunian Analysis

We present the independent photometric detection and statistical validation of TOI-2133b, a sub-Neptunian exoplanet candidate identified by the Transiting Exoplanet Survey Satellite (TESS) and discovered by G. Morello et al. (2026). We began with a sample of 30 Tess Objects of Interest, and performed a vetting pipeline that used Box Least Squares period searches, ground-based differential photometry with the Las Cumbres Observatory Sinistro instrument, and multi-band chromaticity analysis with MuSCAT2 to identify false positives. Once we identified TOI-2133b as the last candidate, a Bayesian transit model fit using the allesfitter package across five TESS sectors was done to yield an orbital period of P= 3.8272 (-0.0021/+0.0029) days and a planetary radius of Rp = 2.37 (-0.28/+0.29) R⊕, placing TOI-2133b in the sub-Neptune regime above the radius gap. Its short-period orbit and equilibrium temperature of approximately 791 K make it a promising target for future atmospheric characterization and atmospheric mass loss studies.