This Hellish Planet Orbits its Star Every 18 Hours. How Did it Get There?

 

Astronomers discovered 55 Cancri e in 2004. That was five years before NASA’s Kepler planet-hunting spacecraft was launched, and exoplanet science has come a long way in the intervening years. Astronomers discovered the planet with the radial velocity method rather than Kepler’s transit method. 55 Cancri e was the first super-Earth found around a main-sequence star. The 55 Cancri system was also the first star discovered with four, and then five, planets.