Discovery image of the exoplanet 51 Eridani b taken in the near-infrared light with the Gemini Planet Imager on Dec. 21, 2014. The bright central star has been mostly removed to enable the detection of the million-times fainter planet.
Credits: Gemini Observatory and J. Rameau (UdeM) and C. Marois NRC Herzberg
One of the best ways to learn how our solar system evolved is to look at younger star systems in the early stages of development. Recently, a team of astronomers including NASA scientists discovered a Jupiter-like planet within a young system that could serve as a decoder ring for understanding how planets formed around our sun. The new planet, called 51 Eridani (Eri) b, is the first exoplanet discovered by the Gemini Planet Imager (GPI), a new instrument operated by an international collaboration, and installed on the 8-meter Gemini South Telescope in Chile. The GPI was designed specifically for discovering and analyzing faint, young planets orbiting bright stars via “direct imaging,” in which astronomers use adaptive optics to sharpen the image of a target star, then block out its starlight. Any remaining incoming light is then analyzed, and the brightest spots indicate a possible planet. “This is exactly the kind of planet we envisioned discovering when we designed GPI”, says James Graham, professor at the University of California, Berkeley, and project scientist for GPI. Other methods of planet detection are indirect, such as the transit method used by NASA’s Kepler mission, in which it discovers planets by measuring the loss of starlight when a planet passes in front of its star. As Bruce Macintosh, a professor of physics at Stanford University and member of the Kavli Institute for Particle Astrophysics and Cosmology figuratively described, to detect planets, Kepler sees their shadow while GPI sees their glow.