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Jupiter-like exoplanets found in sweet spot in most planetary systems
The Gemini Planet Imager searched hundreds of nearby stars for exoplanets using the Gemini South telescope located in the Chilean Andes. Astronomer Marshall Perrin, who received his doctoral degree from Berkeley, is pictured in the foreground with the Magellanic Clouds — two satellite galaxies of the Milky Way — setting in the western sky. (Photo courtesy of Marshall Perrin, Space Telescope Science Institute) As planets form in the swirling gas and dust around young stars, there seems to be a sweet spot where most of the large, Jupiter-like gas giants congregate, centered around the orbit where Jupiter sits today in our own solar system.
The location of this sweet spot is between 3 and 10 times the distance Earth sits from our sun (3-10 astronomical units, or AU). Jupiter is 5.2 AU from our sun.
That’s just one of the conclusions of an unprecedented analysis of 300 stars captured by the Gemini Planet Imager, or GPI, a sensitive infrared detector mounted on the 8-meter Gemini South telescope in Chile.
The GPI Exoplanet Survey, or GPIES, is one of two large projects that search for exoplanets directly, by blocking stars’ light and photographing the planets themselves, instead of looking for telltale wobbles in the star — the radial velocity method — or for planets crossing in front of the star — the transit technique. The GPI camera is sensitive to the heat given off by recently-formed planets and brown dwarfs, which are more massive than gas giant planets, but still too small to ignite fusion and become stars.
The analysis of the first 300 of more than 500 stars surveyed by GPIES, published June 12 in the The Astronomical Journal, “is a milestone,” said Eugene Chiang, a UC Berkeley professor of astronomy and member of the collaboration’s theory group. “We now have excellent statistics for how frequently planets occur, their mass distribution and how far they are from their stars. It is the most comprehensive analysis I have seen in this field.”