OGLE-2018-BLG-0677Lb: A Super-Earth Near the Galactic Bulge

Creators: Herrera-Martín, Antonio; Albrow, M. D.; Udalski, A.; Gould, A.; Ryu, Y.-H.; Yee, J. C.; Chung, S.-J.; Han, C.; Hwang, K.-H.; Jung, Y. K.; Lee, C.-U.; Shin, I.-G.; Shvartzvald, Y.; Zang, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.; Szymański, M. K.; Mróz, P.; Skowron, J.; Poleski, R.; Soszyński, I.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Rybicki, K.; Iwanek, P.; Wrona, M.; KMTNet Collaboration; OGLE Collaboration

Abstract

We report the analysis of the microlensing event OGLE-2018-BLG-0677. A small feature in the light curve of the event leads to the discovery that the lens is a star–planet system. Although there are two degenerate solutions that could not be distinguished for this event, both lead to a similar planet-host mass ratio. We perform a Bayesian analysis based on a Galactic model to obtain the properties of the system and find that the planet corresponds to a super-Earth/sub-Neptune with a mass of M_(planet) = 3.96^(+5.88)_(−2.66) M⊕. The host star has a mass of M_(host) = 0.12^(+0.14)_(−0.08) M⊙. The projected separation for the inner and outer solutions are 0.63^(+0.20)_(−0.17) au and 0.72^(+0.23)_(−0.19) au respectively. At Δχ² = χ² (1L1S) –χ ²(2L1S) = 46, this is by far the lowest Δχ² for any securely detected microlensing planet to date, a feature that is closely connected to the fact that it is detected primarily via a "dip" rather than a "bump."

Additional Information

© 2020 The American Astronomical Society. Received 2020 March 4; revised 2020 April 6; accepted 2020 April 10; published 2020 May 7. A.H.M. and M.D.A. are supported by the Marsden Fund under contract UOC1602. The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to A.U. W.Z. acknowledges support by the National Science Foundation of China (grant No. 11821303 and 11761131004) A.G. received support from the European Research Council under the European Unions Seventh Framework Programme (FP 7) ERC grant Agreement no. [321035] 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 C.H. was supported by the grants (2017R1A4A1015178 and 2019R1A2C2085965) of National Research Foundation of Korea.

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Published - Herrera-Martín_2020_AJ_159_256.pdf

Accepted Version - 2003.02983.pdf

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