Gemini Observatory | 2019 Jun 12
Based on preliminary results from a new Gemini Observatory survey of 531 stars with the Gemini Planet Imager (GPI), it appears more and more likely that large planets and brown dwarfs have very different roots.
The GPI Exoplanet Survey (GPIES), one of the largest and most sensitive direct imaging exoplanet surveys to date, is still ongoing at the Gemini South telescope in Chile. “From our analysis of the first 300 stars observed, we are already seeing strong trends,” said Eric L. Nielsen of Stanford University ...
In November 2014, GPI Principal Investigator Bruce Macintosh of Stanford University and his international team set out to observe almost 600 young nearby stars with the newly commissioned instrument ...
Imaging a planet around another star is a difficult technical challenge possible with only a few instruments. Exoplanets are small, faint, and very close to their host star -- distinguishing an orbiting planet from its star is like resolving the width of a dime from several miles away. Even the brightest planets are ten thousand times fainter than their parent star. GPI can see planets up to a million times fainter, much more sensitive than previous planet-imaging instruments. “GPI is a great tool for studying planets, and the Gemini Observatory gave us time to do a careful, systematic survey,” said Macintosh.
GPIES is now coming to an end. From the first 300 stars, GPIES has detected six giant planets and three brown dwarfs. “This analysis of the first 300 stars observed by GPIES represents the largest, most sensitive direct imaging survey for giant planets published to date,” added Macintosh. Brown dwarfs are more massive than planets, but not massive enough to fuse hydrogen like stars. “Our analysis of this Gemini survey suggests that wide-separation giant planets may have formed differently from their brown dwarf cousins,” Nielsen said.
The team’s paper advances the idea that massive planets form due to the slow accumulation of material surrounding a young star, while brown dwarfs come about due to rapid gravitational collapse. “It’s a bit like the difference between a gentle light rain and a thunderstorm,” said Macintosh. ...
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The Gemini Planet Imager Exoplanet Survey: Giant Planet
and Brown Dwarf Demographics from 10 to 100 au ~ Eric L. Nielsen et al