OGLE-2016-BLG-1227L: A Wide-separation Planet from a Very Short-timescale Microlensing Event
- Creators
- Han, Cheongho
- Udalski, Andrzej
- Gould, Andrew
- Albrow, Michael D.
- Chung, Sun-Ju
- Hwang, Kyu-Ha
- Jung, Youn Kil
- Lee, Chung-Uk
- Ryu, Yoon-Hyun
- Shin, In-Gu
- Shvartzvald, Yossi
- Yee, Jennifer C.
- Zang, Weicheng
- Cha, Sang-Mok
- Kim, Dong-Jin
- Kim, Hyoun-Woo
- Kim, Seung-Lee
- Lee, Dong-Joo
- Lee, Yongseok
- Park, Byeong-Gon
- Pogge, Richard W.
- Jee, M. James
- Kim, Doeon
- Kim, Chun-Hwey
- Kim, Woong-Tae
- Mróz, Przemek
- Szymański, Michał K.
- Skowron, Jan
- Poleski, Radek
- Soszyński, Igor
- Pietrukowicz, Paweł
- Kozlowski, Szymon
- Ulaczyk, Krzysztof
- KMTNet Collaboration
- OGLE Collaboration
Abstract
We present the analysis of the microlensing event OGLE-2016-BLG-1227. The light curve of this short-duration event appears to be a single-lens event affected by severe finite-source effects. Analysis of the light curve based on single-lens single-source (1L1S) modeling yields very small values of the event timescale, t_E ∼ 3.5 days, and the angular Einstein radius, θ_E ∼ 0.009 mas, making the lens a candidate of a free-floating planet. Close inspection reveals that the 1L1S solution leaves small residuals with amplitude ΔI ≲ 0.03 mag. We find that the residuals are explained by the existence of an additional widely-separated heavier lens component, indicating that the lens is a wide-separation planetary system rather than a free-floating planet. From Bayesian analysis, it is estimated that the planet has a mass of _p = 0.79^(+1.30)_(−0.39) M_J and it is orbiting a low-mass host star with a mass of M_(host) = 0.10+0.17−0.05 M_⊙ located with a projected separation of a_ = 3.4^(+2.1)_(−1.0) au. The planetary system is located in the Galactic bulge with a line-of-sight separation from the source star of D_(LS) = 1.21^(+0.96)_(−0.63) kpc. The event shows that there are a range of deviations in the signatures of host stars for apparently isolated planetary lensing events and that it is possible to identify a host even when a deviation is subtle.
Additional Information
© 2020. The American Astronomical Society. Received 2019 November 26; revised 2020 January 8; accepted 2020 January 9; published 2020 February 6. Work by C.H. was supported by the grants of National Research Foundation of Korea (2017R1A4A1015178 and 2019R1A2C2085965). Work by A.G. was supported by US NSF grant AST-1516842 and by JPL grant 1500811. A.G. received support from the European Research Council under the European Union's Seventh Framework Programme (FP 7) ERC Grant Agreement No. [32103]. The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to A.U. 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 R.P. was partly supported by Polish National Agency for Academic Exchange grant Polish Returns 2019. We acknowledge the high-speed internet service (KREONET) provided by Korea Institute of Science and Technology Information (KISTI).Attached Files
Published - Han_2020_AJ_159_91.pdf
Submitted - 1911.11953.pdf
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Additional details
- Eprint ID
- 101163
- Resolver ID
- CaltechAUTHORS:20200206-125056439
- 2017R1A4A1015178
- National Research Foundation of Korea
- 2019R1A2C2085965
- National Research Foundation of Korea
- AST-1516842
- NSF
- 1500811
- JPL
- 32103
- European Research Council (ERC)
- 2014/14/A/ST9/00121
- National Science Centre (Poland)
- Polish National Agency for Academic Exchange
- Created
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2020-02-07Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field