A planet was found near Proxima Centauri. But more interesting than that is how it was found:
Astronomer João Faria and his collaborators detected Proxima Centauri d by measuring tiny shifts in the spectrum of light from the star as the planet’s gravity pulled at it during orbit. The team used a state-of-the art instrument called the Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) at the Very Large Telescope, a system of four 8.2-metre telescopes at the European Southern Observatory in Cerro Paranal, Chile. The results were published on 10 February in Astronomy & Astrophysics1.
This ‘wobble’ technique look for changes in the star’s motion along the line of sight from Earth; ESPRESSO can detect variations of just 10 centimetres per second. The total effect of the planet’s orbit, which takes only 5 days, is about 40 centimetres per second, says Faria, who is at the Institute of Astrophysics and Space Sciences of the University of Porto in Portugal. “I knew that ESPRESSO could do this, but I was still surprised to see it showing up.” .
