The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
Creators: name: Nielsen, Eric L.
name: De Rosa, Robert J.
name: Macintosh, Bruce
name: Wang, Jason J.
name: Ruffio, Jean-Baptiste
name: Chiang, Eugene
name: Marley, Mark S.
name: Saumon, Didier
name: Savransky, Dmitry
name: Ammons, S. Mark
name: Bailey, Vanessa P.
name: Barman, Travis
name: Blain, Celia
name: Bulger, Joanna
name: Chilcote, Jeffrey
name: Cotten, Tara
name: Czekala, Ian
name: Doyon, Rene
name: Duchene, Gaspard
name: Esposito, Thomas M.
name: Fabrycky, Daniel
name: Fitzgerald, Michael P.
name: Follette, Katherine B.
name: Fortney, Jonathan J.
name: Gerard, Benjamin L.
name: Goodsell, Stephen J.
name: Graham, James R.
name: Greenbaum, Alexandra Z.
name: Hibon, Pascale
name: Hinkley, Sasha
name: Hirsch, Lea A.
name: Hom, Justin
name: Hung, Li-Wei
name: Dawson, Rebekah Ilene
name: Ingraham, Patrick
name: Kalas, Paul
name: Konopacky, Quinn
name: Larkin, James E.
name: Lee, Eve J.
name: Lin, Jonathan W.
name: Maire, Jerome
name: Marchis, Franck
name: Marois, Christian
name: Metchev, Stanimir
name: Millar-Blanchaer, Maxwell A.
name: Morzinski, Katie M.
name: Oppenheimer, Rebecca
name: Palmer, David
name: Patience, Jennifer
name: Perrin, Marshall
name: Poyneer, Lisa
name: Pueyo, Laurent
name: Rafikov, Roman R.
name: Rajan, Abhijith
name: Rameau, Julien
name: Rantakyro, Fredrik T.
name: Ren, Bin
name: Schneider, Adam C.
name: Sivaramakrishnan, Anand
name: Song, Inseok
name: Soummer, Remi
name: Tallis, Melisa
name: Thomas, Sandrine
name: Ward-Duong, Kimberly
name: Wolff, Schuyler
Publisher: name: arXiv
Year: 2019
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present a statistical analysis of the first 300 stars observed by the Gemini Planet Imager Exoplanet Survey (GPIES). This subsample includes six detected planets and three brown dwarfs; from these detections and our contrast curves we infer the underlying distributions of substellar companions with respect to their mass, semi-major axis, and host stellar mass. We uncover a strong correlation between planet occurrence rate and host star mass, with stars M $&gt;$ 1.5 $M_\odot$ more likely to host planets with masses between 2-13 M$_{\rm Jup}$ and semi-major axes of 3-100 au at 99.92% confidence. We fit a double power-law model in planet mass (m) and semi-major axis (a) for planet populations around high-mass stars (M $&gt;$ 1.5M$_\odot$) of the form $\frac{d^2 N}{dm da} \propto m^αa^β$, finding $α$ = -2.4 $\pm$ 0.8 and $β$ = -2.0 $\pm$ 0.5, and an integrated occurrence rate of $9^{+5}_{-4}$% between 5-13 M$_{\rm Jup}$ and 10-100 au. A significantly lower occurrence rate is obtained for brown dwarfs around all stars, with 0.8$^{+0.8}_{-0.5}$% of stars hosting a brown dwarf companion between 13-80 M$_{\rm Jup}$ and 10-100 au. Brown dwarfs also appear to be distributed differently in mass and semi-major axis compared to giant planets; whereas giant planets follow a bottom-heavy mass distribution and favor smaller semi-major axes, brown dwarfs exhibit just the opposite behaviors. Comparing to studies of short-period giant planets from the RV method, our results are consistent with a peak in occurrence of giant planets between ~1-10 au. We discuss how these trends, including the preference of giant planets for high-mass host stars, point to formation of giant planets by core/pebble accretion, and formation of brown dwarfs by gravitational instability.
description: 52 pages, 18 figures. AJ in press