TESS observes the WASP-148 system

The hot Jupiter WASP-148b is rather unusual, since it has a sibling planet, WASP-148c in a 35-day orbit (Hébrard et al. 2020). The system was recently observed by TESS leading to a new paper by Gracjan Maciejewski et al. (Nicolaus Copernicus University and the Instituto de Astrofísica de Andalucía).

The gravitational tug of the outer planet WASP-148c perturbs the orbit of the hot Jupiter WASP-148b. Here are deviations in the timings of the hot-Jupiter’s transit (the green points are new timings from TESS, the blue points are from observations from the Sierra Nevada Observatory, the red line is a model based on the masses and orbits of the planets):

The great boon of transit-timing information is that it leads to measurements of the masses of the planets, which can be combined with radial-velocity measurements to give a better overall characterisation of the system.

Maciejewski et al. also searched the TESS data for transits of the outer planet. The yellow areas are the predicted time of transit, should the planet’s orbital inclination be sufficiently high (the red line is a model showing the predicted depth of the transit; the black triangle marks a transit of the hot Jupiter WASP-148b). There is no indication that WASP-148c transits.