Why are Neptune-sized planets rare among exoplanets discovered to date? A ‘warm Neptune’ recently found by astronomers around a bright blue A-type star provides a clue. Astronomers have proposed that gas giants like Neptune would be stripped of their gas in close orbits around a star — the limited region current exoplanet-finding techniques are able to sample. The warm Neptune is just outside the Hot Neptune zone, providing evidence that the theory is correct.
