Wide-Orbit Exoplanets are Common. Analysis of Nearly 20 Years of OGLE Microlensing Survey Data

R. Poleski, J. Skowron, P. Mróz, A. Udalski, M.K. Szymański, P. Pietrukowicz, K. Ulaczyk, K. Rybicki, P. Iwanek, M. Wrona, and M. Gromadzki
2021, Acta Astronomica, 71, 1 (arXiv:2104.02079)

We use nearly 20 years of photometry obtained by the OGLE survey to measure the occurrence rate of wide-orbit (or ice giant) microlensing planets, i.e., with separations from ≈5 AU to ≈15 AU and mass-ratios from 10-4 to 0.033. In a sample of 3112 events we find six previously known wide-orbit planets and a new microlensing planet or brown dwarf OGLE-2017-BLG-0114Lb, for which close and wide orbits are possible and close orbit is preferred. We run extensive simulations of the planet detection efficiency, robustly taking into account the finite-source effects. We find that the extrapolation of the previously measured rate of microlensing planets significantly underpredicts the number of wide-orbit planets. On average, every microlensing star hosts 1.4+0.9-0.6 ice giant planets.

Survey detection efficiency and detected planets

Survey detection efficiency, i.e., number of planets that would be detected if every star had a planet at given separation s and mass ratio q (color scale). Detected planets are marked by black points.

Light curve of OGLE-2017-BLG-0114

Light curve of a new anomalous event OGLE-2017-BLG-0114. The lines show binary-lens models with xallarap effect: close (more likely) and wide.

Data accompanying the paper: link.

PLEASE cite the following paper when using the data or referring to these OGLE results:
    Poleski et al., 2021, Acta Astronomica, 71, 1 (arXiv:2104.02079)

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