Exoplanet
A planet situated outside the Solar System that orbits a star, stellar remnant, or brown dwarf.
Governing formula
Transit Depth ΔF / F = (R_planet / R_star)²
SI unit
Earth Masses (M_⊕) or Jupiter Masses (M_J)
In depth
Discovered primarily via the Transit Method (measuring periodic starlight dimming) and Radial Velocity Method (detecting Doppler wobbles). Planetary habitability requires orbiting within the circumstellar habitable zone.
Examples in the real world
Kepler-186f, an Earth-sized exoplanet orbiting within the habitable zone of a red dwarf star.