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Spitzer Opens New Path to Break Classic Degeneracy for Jupiter-Mass Microlensing Planet OGLE-2017-BLG-1140Lb
- Source :
- The Astronomical Journal, 155, 261, (2018)
- Publication Year :
- 2018
-
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 $(m_p\simeq 1.6\,M_{\rm jup})$ planet orbiting a mid-late M dwarf $(M\simeq 0.2\,M_\odot)$ that lies $D_{LS}\simeq 1.0\,\mathrm{kpc}$ in the foreground of the microlensed, Galactic-bar, source star. The planet-host projected separation is $a_\perp \simeq 1.0\,\mathrm{au}$, i.e., well-beyond the snow line. By measuring the source proper motion ${\mathbf{\mu}}_s$ from ongoing, long-term OGLE imaging, and combining this with the lens-source relative proper motion ${\mathbf{\mu}}_\mathrm{rel}$ derived from the microlensing solution, we show that the lens proper motion ${\mathbf{\mu}}_l={\mathbf{\mu}}_\mathrm{rel} + {\mathbf{\mu}}_s$ 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) models and by binary-source (1L2S) models, the combination of Spitzer and ground-based data decisively favor the planetary model. This is a new channel to resolve the 2L1S/1L2S degeneracy, which can be difficult to break in some cases.<br />Comment: Revised version accepted for publication in The Astronomical Journal
Details
- Database :
- arXiv
- Journal :
- The Astronomical Journal, 155, 261, (2018)
- Publication Type :
- Report
- Accession number :
- edsarx.1803.04437
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.3847/1538-3881/aac21c