An exciting new tool for exoplanet discovery was revealed at this week’s 223rd meeting of the American Astronomical Society being held in Washington D.C.
On Tuesday, researchers unveiled the first new images from the Gemini Observatory’s Gemini Planet Imager (GPI). Based at the Gemini South Telescope in Chile, the GPI saw first light this past November, and operates at near-infrared wavelengths that will allow it to directly detect exoplanets in orbit around nearby stars.
“Even these early first-light images are almost a factor of 10 better than the previous generation of instruments,” said the Lawrence Livermore National Laboratory’s Bruce Macintosh. “In one minute, we are seeing planets that used to take us an hour to detect.”
The Gemini Planet Imager focused on the known gas giant planet orbiting the star Beta Pictoris in the southern hemisphere constellation of Pictor, revealing the world in unprecedented resolution. At about 4 to 10 Jupiter masses, Beta Pictoris b orbits it host star at a distance of nine times the Earth-Sun distance and is 63 light years away. Beta Pictoris b is one of the very few exoplanets to have been directly imaged.
The team also focused the Gemini Planet Imager on the young star HR4796A, revealing the dusty disk surrounding the star. Such techniques may soon be able to catch young solar systems “in the act” of formation, and provide astronomers with key insights into how planetary systems such as our own were formed.
The chief difficultly in seeing exoplanets directly lies in the fact that they are located near their bright parent star, which swamps the view with light. The Gemini Planet imager gets around this by use of adaptive optics and a coronagraph with which to occult or cover up the host star, revealing the nearby planet shining at near-infrared wavelengths.
The Gemini Planet Imager will also open up possibilities for characterizing extrasolar planets as well. Not much is known about planets that are detected by radial velocity measurements or stellar transits; astronomers can only infer the orbital period and perhaps the lower limits on mass and radius from these indirect methods. But if a direct image of an exoplanet can be obtained, researchers can then gather a spectra that can tell us much more about the atmospheric composition of a distant world.
“Most planets that we know about to date are only known because of indirect methods that tell us a planet is there, a bit about its orbit and mass, but not much else,” said Macintosh. “With GPI we directly image planets around stars – it’s a bit like being able to detect the system and really dive into the planet’s atmospheric makeup and characteristics.”
And although the detector was made for exoplanet hunting, it can take some amazing images of objects in our own solar system as well. Check out this test image of Jupiter’s moon Europa taken with the GPI:
Congratulations to the team at Lawrence Livermore and Gemini South on ushering in a new era of exoplanet astronomy.