Discovery of 55 Cancri b

55 Cancri b was the first planet found around the star 55 Cancri, which is a sun-like star in the constellation Cancer, about forty light-years away. Paul Butler and Geoffrey Marcy discovered it in 1996 by measuring tiny shifts in the star's spectrum caused by the planet's gravity, a method known as the radial velocity technique. It orbits the star about every fourteen days and is a gas giant with a mass somewhat below that of Jupiter. It was one of the earliest exoplanets found after 51 Pegasi b in 1995. Four more planets were later discovered around the same star, making a multi-planet system.

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