Wed, March 14, 2018
Time: 12:30 – 1:30pm
Location: 131 Campbell Hall.
Speaker: Eric Nielsen (Stanford)
Title: The Gemini Planet Imager Exoplanet Survey: a Trend in Wide Separation Giant Planets Occurrence Rate with Stellar Mass
GPIES (The Gemini Planet Imager Exoplanet Survey) is an 600-star survey to detect and characterize giant planets between 5 and 100 AU orbiting young, nearby stars. GPI combines a high order adaptive optics systems, an apodized Lyot coronagraph, and an integral field spectrograph to reach contrasts of 15 magnitudes within 0.5" of the central star. I present an overview of the highlights from the survey, including the recovery of known planets and brown dwarfs around our target stars, and the discovery of 51 Eridani b, a 2 Jupiter mass planet orbiting 13 AU from its star, and characterization of its atmosphere and orbit since the discovery. I also present the cautionary tale of the putative giant planet HD 131399 Ab, where GPI observations found this object to in fact be a background star, and the lessons for planet imaging going forward. One of the key goals of GPIES is to directly measure the occurrence rate of wide-separation giant planets, and I present early results on this front based on an analysis of the first half of the survey. For the first time we are seeing a trend in occurrence rate with stellar mass, which has profound implications for how these planets form and evolve.