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Spitzer Opens New Path to Break Classic Degeneracy for Jupiter-mass Microlensing Planet OGLE-2017-BLG-1140Lb

Calchi Novati, S. and Beichman, C. and Carey, S. and Henderson, C. B. (2018) Spitzer Opens New Path to Break Classic Degeneracy for Jupiter-mass Microlensing Planet OGLE-2017-BLG-1140Lb. Astronomical Journal, 155 (6). Art. No. 261. ISSN 1538-3881. doi:10.3847/1538-3881/aac21c.

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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 ≃ 1.6 M_(Jup)) planet orbiting a mid-late M dwarf (M ≃ 0.2 M⊙) that lies D_(LS) ≃ 1.0 kpc in the foreground of the microlensed Galactic-bar source star. The planet–host projected separation is a⊥ ≃ 1.0 au, i.e., well beyond the snow line. By measuring the source proper motion µ_s from ongoing long-term OGLE imaging and combining this with the lens-source relative proper motion µ_(rel) derived from the microlensing solution, we show that the lens proper motion µ_l = µ(rel) + µ_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)) 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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Calchi Novati, S.0000-0002-7669-1069
Beichman, C.0000-0002-5627-5471
Carey, S.0000-0002-0221-6871
Henderson, C. B.0000-0001-8877-9060
Additional Information:© 2018 The American Astronomical Society. Received 2018 March 12; revised 2018 April 20; accepted 2018 April 30; published 2018 June 1. The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to AU. Work by YKJ and AG was supported by AST-1516842 from the US NSF. IGS and AG were supported by JPL grant 1500811. This research has made use of the KMTNet system operated by the Korea Astronomy and Space Science Institute (KASI), and the data were obtained at three host sites of CTIO in Chile, SAAO in South Africa, and SSO in Australia. Work by YS was supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, California Institute of Technology, administered by Universities Space Research Association through a contract with NASA. Work by C. Han was supported by a grant (2017R1A4A1015178) of the National Research Foundation of Korea. This work is based (in part) on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. This work was partially supported by NASA contract NNG16PJ32C.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
National Science Centre (Poland)MAESTRO 2014/14/A/ST9/00121
NASA Postdoctoral ProgramUNSPECIFIED
National Research Foundation of Korea2017R1A4A1015178
Subject Keywords:gravitational lensing: micro
Issue or Number:6
Record Number:CaltechAUTHORS:20180601-124053446
Persistent URL:
Official Citation:S. Calchi Novati et al 2018 AJ 155 261
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86743
Deposited By: Tony Diaz
Deposited On:01 Jun 2018 20:20
Last Modified:15 Nov 2021 20:41

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