A single 21-hour, 1.1% symmetric transit in 2019 TESS data points to a massive companion orbiting Tabby’s Star, the first specific object tied to the system’s long-mysterious fading.
Joint fitting of that transit with reprocessed SOPHIE radial-velocity data suggests a roughly 9.4-Jupiter-mass gas giant on a near-circular, roughly three-year orbit about 2.35 AU from the star.
The planet could solve the key gap in the leading exocomet theory by gravitationally perturbing icy bodies inward, producing the irregular, asymmetric dips that have reached 22% and baffled astronomers since 2015.
The case remains tentative at 2.3 sigma and rests on one transit, with the orbital period narrowed to five windows rather than fixed.
October 18-23, 2026 is the next crucial test window: a confirmed transit could lock down the orbit, while Gaia DR4 and possible JWST follow-up offer independent checks.