The Gemini Planet Imager (GPI) is an instrument on the Gemini South telescope designed to directly image and characterize extrasolar planets. GPI was built by a consortium of institutions led by Bruce Macintosh of Stanford University and James Lloyd of the Massachusetts Institute of Technology.
GPI is a high-contrast imaging instrument, meaning that it is designed to take pictures of faint objects next to much brighter objects. In this case, the targets are young Jupiter-like planets orbiting nearby stars. To do this, GPI uses two main technologies. First, an adaptive optics system corrects for the blurring effects of Earth’s atmosphere in real time. Second, a coronagraph blocks out most of the light from the central star, allowing the fainter planet to be seen.
GPI also has several other features that make it well suited for characterizing extrasolar planets. It has a very stable infrared camera that can take very precise measurements. Additionally, GPI can measure the polarization of light coming from a planet, which can be used to infer the presence of clouds or hazes in its atmosphere.
Since its commissioning in 2014, GPI has taken some groundbreaking images and made important discoveries about extrasolar planets. In 2015, it captured one of the first direct images of an exoplanet: PSO J318.5-22, a gas giant about 13 times the mass of Jupiter orbiting a young star 840 light years away. This was also one of the first exoplanets imaged with polarized light, revealing evidence for atmospheric scattering by clouds or haze particles.
In 2016, GPI discovered 51 Pegasi b around 25 years after it became famous as “the first exoplanet found orbiting a sun-like star” using radial velocity methods rather than direct imaging . This discovery was particularly exciting because 51 Pegasi b is only about half as massive as Jupiter but orbits much closer to its host star than Mercury does to our Sun—a so-called “hot Jupiter.” These close-in giant planets are thought to have migrated inward during their formation process and provide clues about how planetary systems form and evolve over time . More recently , in 2018 , GPI made another important discovery when it found evidence for cloud cover on HR 8799c , one HR 8799b – making it only The second self-luminous world – after our own Solar System’s Neptune – where researchers have been able confirm detection An atmosphere . As technology improves , we can expect even more amazing discoveries from this powerful tool in future studies Of Extrasolar Planet atmospheres .