Gliese 876 d

Gliese 876 d is an exciting object in space called an exoplanet. It is located about 15.2 light-years from Earth, which is about 4.7 parsecs, in the constellation of Aquarius. This planet orbits a small, cool star known as a red dwarf called Gliese 876.

Gliese 876 d was discovered as the third planet around its star. When it was found, it was the smallest planet known outside our solar system, except for some planets found around a special type of star called a pulsar, such as those orbiting PSR B1257+12. Because of its size and mass, Gliese 876 d is classified as a super-Earth, meaning it is bigger and more massive than our Earth but smaller than most planets like Neptune.

This planet helps scientists learn more about how planets form and what kinds of worlds might exist around other stars. Its discovery was an important step in finding and studying planets beyond our solar system.

Characteristics

The planet Gliese 876 d is very small, with a mass about 6.83 times that of Earth. Scientists think it might be a rocky planet, similar to Earth, or it could have formed farther from its star and moved closer, possibly having water inside.

Gliese 876 d orbits a small, cool star called Gliese 876, which is much smaller and cooler than our Sun. The planet is very close to its star, only about 3.11 million kilometers away, but its orbit is stretched out rather than perfectly circular.

Discovery

Gliese 876 d was discovered by studying changes in its star's radial velocity caused by the planet's gravity. Scientists observed the Doppler shift in the star's spectral lines to measure these changes. At the time, two other planets, Gliese 876 b and c, were already known to orbit the star. After accounting for these two planets, researchers noticed another pattern in the data, indicating a third planet. This new planet, Gliese 876 d, was announced on June 13, 2005 by a team led by Eugenio Rivera. It was found to have a mass about 7.5 times that of Earth.