A planetary companion has been detected circling the star HD 73256, bringing to 106 the total number of planets thus far discovered orbiting stars other than our Sun. The planet is one of a class known as "hot jupiters" -- gas giants located in tight orbits extremely close to their parent stars.

The discovery was made by a team of European astronomers carrying out precise Doppler observations at the La Silla Observatory in Chile. Their method of detection, called radial velocity, or Doppler spectroscopy, infers the presence of an unseen companion because of the back-and-forth movement it induces in the host star. A planet exerts a small gravitational pull on its parent star, causing the star to wobble. The motion amplitude depends on the orbital distance and mass of the planet. This movement is detectable as a periodic red shift and blue shift in the star's spectral lines.

Full story at Astrobiology Magazine