TOI-2535b, a hot Jupiter, vanished from TESS transits over 7 years of data

A team of astronomers has reported the hot Jupiter TOI-2535b, the first confirmed planet orbiting a single star whose transits have been directly observed to disappear. The work was published in The Astrophysical Journal Letters. The authors used more than 7 years of photometry from NASA's Transiting Exoplanet Survey Satellite (TESS) iop.orgThe Astrophysical Journal Lettersiop.orgOpen source ↗.

Over this period, the planet's transit chord crossed the stellar disk and eventually moved off it entirely. The impact parameter changed at a rate of 0.16 per year. A transit is visible only when the planet's orbit is aligned with our line of sight, and here that alignment proved temporary, according to the authors.

Timing and duration variations

The transit midtimes also depart significantly from a linear ephemeris, by about ±6 hours. The researchers modeled the transit timing variations (TTVs) and transit duration variations (TDVs) jointly with radial-velocity data from the NEID spectrograph.

The modeling indicates a nearby planetary perturber whose orbit is mutually inclined to that of TOI-2535b by about 5 degrees or more iop.orgThe Astrophysical Journal Lettersiop.orgOpen source ↗. According to the authors, the duration variations are driven mainly by precession of the planets' orbital planes.

A second giant planet in resonance

The dynamical modeling suggests that the perturber is likely of Saturn mass or greater and is in a mean-motion resonance with TOI-2535b. This makes the system unusual, since it contains two short-period giant planets.

The authors describe the TDVs measured for TOI-2535b as one of the most extreme examples of planet–planet interactions driving orbital evolution on human timescales. The perturber is inferred from timing, duration and radial-velocity modeling rather than from its own transits.