Astronomical objects are often designated a catalog indicator (an abbreviation) followed either by a number, sometimes indicating the order of discovery, or by a J designator indicating position in the celestial sphere. Each survey, or discovery mission/project in effect produces a catalog, for which these indicators of its discovered objects reveal the mission that found them.
Extra-solar planets are all relatively new discoveries and generally designated in this manner. A final number or letter suffix may indicate which planet of a planet-bearing system, or which star of a multi-star system.
See examples in the Catalogs/Surveys table.