Dispersed Matter Planet Project discoveries of ablating planets orbiting nearby bright stars

Some highly irradiated close-in exoplanets orbit stars showing anomalously low stellar chromospheric emission. We attribute this deficit to absorption by circumstellar gas replenished by mass loss from ablating planets. Here we report statistics validating this hypothesis. Among ~3,000 nearby, bright, main-sequence stars, ~40 show depressed chromospheric emission indicative of undiscovered mass-losing planets. The Dispersed Matter Planet Project uses high-precision, high-cadence radial velocity (RV) measurements to detect these planets. We summarize results for two planetary systems (DMPP-1 and DMPP-3) and fully present observations revealing an Mp sin i = 0.469 MJ planet in a 5.207 d orbit around the γ Doradus pulsator HD 11231 (DMPP-2). We have detected short-period planets wherever we have made more than 60 RV measurements, demonstrating that we have originated a very efficient method for detecting nearby compact planetary systems. These shrouded, ablating planetary systems may be a short-lived phase related to the Neptunian desert, that is, the dearth of intermediate-mass planets at short orbital periods. The circumstellar gas facilitates compositional analysis, allowing empirical exogeology in the cases of sublimating rocky planets. Dispersed Matter Planet Project discoveries will be important for establishing the empirical mass–radius–composition relationship(s) for low-mass planets. This Article provides an overview of the Dispersed Matter Planet Project, a programme to discover close-in exoplanets being ablated by their host stars by means of the stars’ anomalously low chromospheric emission. One example is presented here: DMPP-2 hosts a sub-Jupiter-mass planet around a γ Doradus pulsator.