The Leech Exoplanet Imaging Survey: Limits On Planet Occurrence Rates Under Conservative Assumptions

Authors

• Jordan M. Stone, The University of Arizona
• Andrew J. Skemer, University of California, Santa Cruz
• Philip M. Hinz, The University of Arizona
• Mariangela Bonavita, University of Edinburgh, Institute for Astronomy
• Kaitlin M. Kratter, The University of Arizona
• Anne Lise Maire, Max Planck Institute for Astronomy
• Denis Defrere, Université de Liège
• Vanessa P. Bailey, Jet Propulsion Laboratory
• Eckhart Spalding, The University of Arizona
• Jarron M. Leisenring, The University of Arizona
• S. Desidera, Osservatorio Astronomico di Padova
• M. Bonnefoy, Université Grenoble Alpes
• Beth Biller, University of Edinburgh, Institute for Astronomy
• Charles E. Woodward, University of Minnesota Twin Cities
• Th Henning, Max Planck Institute for Astronomy
• Michael F. Skrutskie, University of Virginia
• J. A. Eisner, The University of Arizona
• Justin R. Crepp, University of Notre Dame
• Jennifer Patience, School of Earth and Space Exploration
• Gerd Weigelt, Max Planck Institute for Radio Astronomy
• Robert J. De Rosa, University of California, Berkeley
• Joshua Schlieder, Max Planck Institute for Astronomy
• Wolfgang Brandner, Max Planck Institute for Astronomy
• Dániel Apai, The University of Arizona
• Kate Su, The University of Arizona
• Steve Ertel, The University of Arizona
• Kimberly Ward-Duong, Amherst CollegeFollow
• Katie M. Morzinski, The University of Arizona
• Dieter Schertl, Max Planck Institute for Radio Astronomy
• Karl Heinz Hofmann, Max Planck Institute for Radio Astronomy
• Laird M. Close, The University of Arizona
• Stefan S. Brems, Landessternwarte Heidelberg

Document Type

Article

Publication Date

1-1-2018

Publication Title

Astronomical Journal

Abstract

We present the results of the largest L' (3.8 μm) direct imaging survey for exoplanets to date, the Large Binocular Telescope Interferometer Exozodi Exoplanet Common Hunt (LEECH). We observed 98 stars with spectral types from B to M. Cool planets emit a larger share of their flux in L' compared to shorter wavelengths, affording LEECH an advantage in detecting low-mass, old, and cold-start giant planets. We emphasize proximity over youth in our target selection, probing physical separations smaller than other direct imaging surveys. For FGK stars, LEECH outperforms many previous studies, placing tighter constraints on the hot-start planet occurrence frequency interior to ~20 au. For less luminous, cold-start planets, LEECH provides the best constraints on giant-planet frequency interior to ~20 au around FGK stars. Direct imaging survey results depend sensitively on both the choice of evolutionary model (e.g., hot- or coldstart) and assumptions (explicit or implicit) about the shape of the underlying planet distribution, in particular its radial extent. Artificially low limits on the planet occurrence frequency can be derived when the shape of the planet distribution is assumed to extend to very large separations, well beyond typical protoplanetary dust-disk radii (≤50 au), and when hot-start models are used exclusively. We place a conservative upper limit on the planet occurrence frequency using coldstart models and planetary population distributions that do not extend beyond typical protoplanetary dust-disk radii. We find that ≤90% of FGK systems can host a 7-10 MJupplanet from 5 to 50 au. This limit leaves open the possibility that planets in this range are common.

Keywords

Gaseous planets - stars, High angular resolution, Imaging - techniques, Planetary systems - planets and satellites

Volume

156

Issue

6

DOI

https://doi.org/10.3847/1538-3881/AAEC00

ISSN

00046256

Rights

© 2018. The American Astronomical Society.

Version

Version of Record

Recommended Citation

Stone, Jordan M.; Skemer, Andrew J.; Hinz, Philip M.; Bonavita, Mariangela; Kratter, Kaitlin M.; Maire, Anne Lise; Defrere, Denis; Bailey, Vanessa P.; Spalding, Eckhart; Leisenring, Jarron M.; Desidera, S.; Bonnefoy, M.; Biller, Beth; Woodward, Charles E.; Henning, Th; Skrutskie, Michael F.; Eisner, J. A.; Crepp, Justin R.; Patience, Jennifer; Weigelt, Gerd; De Rosa, Robert J.; Schlieder, Joshua; Brandner, Wolfgang; Apai, Dániel; Su, Kate; Ertel, Steve; Ward-Duong, Kimberly; Morzinski, Katie M.; Schertl, Dieter; Hofmann, Karl Heinz; Close, Laird M.; and Brems, Stefan S., "The Leech Exoplanet Imaging Survey: Limits On Planet Occurrence Rates Under Conservative Assumptions" (2018). Astronomy: Faculty Publications, Smith College, Northampton, MA.
https://scholarworks.smith.edu/ast_facpubs/125