Which exoplanet was the first super-Earth found around a main-sequence star?

Gliese 876 d was the first super-Earth discovered around a main-sequence star.

A team led by Eugenio Rivera announced Gliese 876 d on June 13, 2005. Astronomers found it by measuring Doppler shifts in the spectrum of its host star: the planet’s gravity makes the star move slightly toward and away from Earth.

The discovery was historically important because earlier super-Earths had been found around the pulsar PSR B1257+12, not a normal main-sequence star. Gliese 876 d orbits Gliese 876, a small red dwarf in Aquarius, and was the third planet known in that system at the time.

Gliese 876 d is not considered an Earth twin. Its estimated mass is several times Earth’s, its orbit takes only about two days, and its equilibrium temperature is roughly 614 kelvins. Because radial-velocity measurements provide a minimum mass unless the orbital inclination is known, early descriptions commonly gave about 7.5 Earth masses, while later modeling estimated about 6.8.