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MOA-2016-BLG-319Lb: Microlensing Planet Subject to Rare Minor-image Perturbation Degeneracy in Determining Planet Parameters

Han, Cheongho and Shvartzvald, Yossi (2018) MOA-2016-BLG-319Lb: Microlensing Planet Subject to Rare Minor-image Perturbation Degeneracy in Determining Planet Parameters. Astronomical Journal, 156 (5). Art. No. 226. ISSN 1538-3881. https://resolver.caltech.edu/CaltechAUTHORS:20181026-101110631

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Abstract

We present the analysis of the planetary microlensing event MOA-2016-BLG-319. The event light curve is characterized by a brief (~3 days) anomaly near the peak produced by minor-image perturbations. From modeling, we find two distinct solutions that describe the observed light curve almost equally as well. From the investigation of the lens-system configurations, we find that the confusion in the lensing solution is caused by the degeneracy between the two solutions resulting from the source passages on different sides of the planetary caustic. These degeneracies can be severe for major-image perturbations, but it is known that they are considerably less severe for minor-image perturbations. From the comparison of the lens-system configuration with those of two previously discovered planetary events, for which similar degeneracies were reported, we find that the degeneracies are caused by the special source trajectories that passed the star–planet axes at approximately right angles. By conducting a Bayesian analysis, it is estimated that the lens is a planetary system in which a giant planet with a mass M_p = 0.62^(+1.16)_(-0.33) M_J (0.65^(+1.21)_(-0.35) M_J) is orbiting a low-mass M-dwarf host with a mass M_h = 0.15^(+0.28)_(-0.08) M⊙ . Here the planet masses in and out of the parentheses represent the masses for the individual degenerate solutions. The projected host-planet separations are a⊥ ~ 0.95 and ~1.05 au for the two solutions. The identified degeneracy indicates the need to check similar degeneracies in future analyses of planetary lensing events with minor-image perturbations.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/1538-3881/aae38eDOIArticle
https://arxiv.org/abs/1809.07898arXivDiscussion Paper
ORCID:
AuthorORCID
Han, Cheongho0000-0002-2641-9964
Shvartzvald, Yossi0000-0003-1525-5041
Additional Information:© 2018 The American Astronomical Society. Received 2018 August 19; revised 2018 September 17; accepted 2018 September 20; published 2018 October 26. Work by C.H. was supported by the grant (2017R1A4A1015178) of National Research Foundation of Korea. Work by A.G. was supported by US NSF grant AST-1516842. Work by I.G.S. and A.G. was 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. The MOA project was supported by JSPS KAKENHI grant No. JSPS24253004, JSPS26247023, JSPS23340064, JSPS15H00781, and JP16H06287. D.P.B., A.B., and C.R. were supported by NASA through grant NASA-80NSSC18K0274. The work by C.R. was supported by an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by USRA through a contract with NASA. N.J.R. is a Royal Society of New Zealand Rutherford Discovery Fellow. We acknowledge the high-speed internet service (KREONET) provided by Korea Institute of Science and Technology Information (KISTI).
Group:Infrared Processing and Analysis Center (IPAC)
Funders:
Funding AgencyGrant Number
National Research Foundation of Korea2017R1A4A1015178
NSFAST-1516842
JPL1500811
Japan Society for the Promotion of Science (JSPS)JSPS24253004
Japan Society for the Promotion of Science (JSPS)JSPS26247023
Japan Society for the Promotion of Science (JSPS)JSPS23340064
Japan Society for the Promotion of Science (JSPS)JSPS15H00781
Japan Society for the Promotion of Science (JSPS)JP16H06287
NASA80NSSC18K0274
NASA Postdoctoral ProgramUNSPECIFIED
Royal Society of New ZealandUNSPECIFIED
Subject Keywords:gravitational lensing: micro – planetary systems
Issue or Number:5
Record Number:CaltechAUTHORS:20181026-101110631
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20181026-101110631
Official Citation:Cheongho Han et al 2018 AJ 156 226
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90428
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:26 Oct 2018 17:37
Last Modified:03 Oct 2019 20:25

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