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Published September 2020 | Version Published + Submitted
Journal Article Open

OGLE-2018-BLG-1269Lb: A Jovian Planet with a Bright I = 16 Host

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Abstract

We report the discovery of a planet in the microlensing event OGLE-2018-BLG-1269 with a planet–host mass ratio q ~ 6 × 10⁻⁴, i.e., 0.6 times smaller than the Jupiter/Sun mass ratio. Combined with the Gaia parallax and proper motion, a strong one-dimensional constraint on the microlens parallax vector allows us to significantly reduce the uncertainties of lens physical parameters. A Bayesian analysis that ignores any information about light from the host yields that the planet is a cold giant M₂ = (0.69)_(-0.22)^(+0.44) M_J orbiting a Sun-like star M₁ = 1.13_(-0.35)^(+0.72) M_⊙ at a distance of D_L = 2.56_(-0.62)^(+0.92) kpc. The projected planet–host separation is a_⟂ = 4.61_(-1.17)^(+1.70) au. Using Gaia astrometry, we show that the blended light lies ≾ 12 mas from the host and therefore must be either the host star or a stellar companion to the host. An isochrone analysis favors the former possibility at >99.6%. The host is therefore a subgiant. For host metallicities in the range of 0.0 ⩽ [Fe/H] ⩽ +0.3, the host and planet masses are then in the range of 1.16 ⩽ M_₁/M_⊙ ⩽ 1.38 and 0.74 ⩽ M_₂/M_J⩽ 0.89, respectively. Low host metallicities are excluded. The brightness and proximity of the lens make the event a strong candidate for spectroscopic follow-up both to test the microlensing solution and to further characterize the system.

Additional Information

© 2020. The American Astronomical Society. Received 2020 June 28; revised 2020 July 26; accepted 2020 August 1; published 2020 September 2. 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 the three host sites of CTIO in Chile, SAAO in South Africa, and SSO in Australia. A.G. was supported by JPL grant 1500811. Work by C.H. was supported by grants of the National Research Foundation of Korea (2017R1A4A1015178 and 2019R1A2C2085965). The OGLE has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to A.U. The MOA project is supported by JSPS KAKENHI grant Nos. JSPS24253004, JSPS26247023, JSPS23340064, JSPS15H00781, JP16H06287, and 19KK0082.

Attached Files

Published - Jung_2020_AJ_160_148.pdf

Submitted - 2006.15774.pdf

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2006.15774.pdf

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Additional details

Identifiers

Eprint ID
105335
Resolver ID
CaltechAUTHORS:20200911-133134585

Related works

Describes
https://arxiv.org/abs/2006.15774 (URL)

Funding

Korea Astronomy and Space Science Institute (KASI)
JPL
1500811
National Research Foundation of Korea
2017R1A4A1015178
National Research Foundation of Korea
2019R1A2C2085965
National Science Centre (Poland)
MAESTRO 2014/14/A/ST9/00121
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
Japan Society for the Promotion of Science (JSPS)
JP19KK0082

Dates

Created
2020-09-15
Created from EPrint's datestamp field
Updated
2021-11-16
Created from EPrint's last_modified field

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Caltech groups
Infrared Processing and Analysis Center (IPAC)