Entrada Departament News A planet in a star next door

A planet in a star next door

A team led by Xavier Dumusque, which includes Nuno Santos from CAUP, announced the discovery of a planet orbiting Alpha Centauri B, the closest star system to the Sun
A planet in a star next door

Artistic impression of a planet in alpha centauri B(ESO/L. Calçada)

A star at a distance of four light years, in galactic terms, is next door. This discovery was announced in Nature,  in a paper entitled An Earth mass planet orbiting Alpha Centauri B, was based on the method of measuring variations of the radial velocity of the star.

Two bodies under gravitational attraction orbit each other around a point called the center of mass of the system. In the case of a star and a planet, where the mass of the latter is much higher than that of the former, the center of mass is very near the center of the star and ist movement is a orbit of extremely small radius (much smaller than the radius star). Still, the speed of the star in our line of sight (radial velocity) has a small oscillation. This team used an instrument designed specifically to measure these changes with great precision - High Accuracy Radial Velocity Planet Searcher (HARPS) - installed at the European Southern Observatory at La Silla in Chile.

Nuno Santos is a researcher in CAUP (Center for Astrophysics in Porto University) whose success in detecting exoplanets has earned him the nickname of planet hunter.

Although the possibility of travelling to another solar system is but a dream, the possibility of existence of Earth-like planets so close, in a universe so vast fires  our imagination: this discovery had a  huge media coverage worldwide. Here are some links to stories in the media:

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