2018/03/31 by S. Calchi Novati, J. Skowron, Y. K. Jung +48
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Brown dwarf #Bulge #Degeneracy (biology) #Gravitational microlensing #Planet #Planetary system #Proper motion #Stellar, planetary, and galactic studies #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/aac21c
published as The Astronomical Journal, 155, 261, (2018) · Revised version accepted for publication in The Astronomical Journal
openalex created_date 2018/03/29 · arxiv created 2018/04/30 · openalex publication_date 2018/06/01 · arxiv updated 2018/08/14 · openalex updated_date 2026/08/06
Abstract We analyze the combined Spitzer and ground-based data for OGLE-2017-BLG-1140 and show that the event was generated by a Jupiter-class planet orbiting a mid-late M dwarf that lies in the foreground of the microlensed Galactic-bar source star. The planet–host projected separation is , i.e., well beyond the snow line. By measuring the source proper motion from ongoing long-term OGLE imaging and combining this with the lens-source relative proper motion derived from the microlensing solution, we show that the lens proper motion is consistent with the lens lying in the Galactic disk, although a bulge lens is not ruled out. We show that while the Spitzer and ground-based data are comparably well fitted by planetary (i.e., binary-lens (2L1S)) and binary-source (1L2S) models, the combination of Spitzer and ground-based data decisively favors the planetary model. This is a new channel to resolve the 2L1S/1L2S degeneracy, which can be difficult to break in some cases.