Planet populations inferred from debris discs

We know little about the outermost exoplanets in planetary systems because our detection methods are insensitive to moderate-mass planets on wide orbits. However, debris discs can probe outer-planet population dynamical modelling of observed reveal properties perturbing planets. use four sculpting and stirring arguments infer planet 178 debris-disc from ISPY, LEECH, LIStEN planet-hunting surveys. Similar analyses often conducted for individual discs, but we consider a large sample consistent manner. aim predict wide-separation planets, gain insight into formation evolution histories systems, determine feasibility detecting these near future. show that ‘typical’ cold disc likely requires Neptune- Saturn-mass at 10–100 au, with some needing Jupiter-mass perturbers. Our predicted currently undetectable, modest detection-limit improvements (e.g. JWST) should many such find thought be late times similar those inferred forming protoplanetary so could same if newly formed do not migrate as far thought. Alternatively, young rapidly sculpt before migrating inwards, meaning responsible more massive (and located farther inwards) than studies assume. combine self-stirring size-distribution cannot self-stirred without having unreasonably high masses; planet- or companion-stirring may therefore dominant mechanism (perhaps all) discs. Finally, provide catalogues predictions identify promising targets future searches.