Analysis of an Ambiguous Transit Detection of the Hot Jupiter Candidate TOI-3777.01

The Transiting Exoplanet Survey Satellite (TESS) identified TOI-3777.01 as a candidate Hot Jupiter orbiting a faint (V=13.63) F-type star with a period of 2.34 days. We present an analysis of a ground-based follow-up observation using the George Mason University 0.8-meter telescope on UT 2024-02-05. We analyze the data using aperture photometry and light curve modeling with AstroImageJ. We detect a minimal transitlike signal. Our best-fit model gives an estimated depth of 4.92 ppt, which corresponds to a planet radius of 0.89 RJup (this assumes that the signal is on the target star and not diluted) and suggests that the transit occurred about 4.3 minutes later than predicted. However, the detection has a low signal-to-noise ratio (SNR = 0.57), which means the noise (8.60 ppt RMS) is high compared to the signal and, therefore, the results are marginal. Furthermore, observations were taken during poor atmospheric conditions (FWHM ≈ 4.4′′). This caused a blending between the target (T1) and a nearby star (C2) located only 2′′ away. Because the stars are blended together in the images, we see a dip in the light from both stars, making it impossible to distinguish which star the transit occurred on. We conclude that this observation is inconclusive and cannot validate TOI-3777.01. Higher resolution imaging and better precision measurements are needed to confirm the candidate.