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KMT-2017-BLG-0165Lb: A Super-Neptune-mass Planet Orbiting a Sun-like Host Star

Jung, Youn Kil and Gould, Andrew and Zang, Weicheng and Hwang, Kyu-Ha and Ryu, Yoon-Hyun and Han, Cheongho and Yee, Jennifer C. and Albrow, Michael D. and Chung, Sun-Ju and Shin, In-Gu and Shvartzvald, Yossi and Zhu, Wei and Cha, Sang-Mok and Kim, Dong-Jin and Kim, Hyoun-Woo and Kim, Seung-Lee and Lee, Chung-Uk and Lee, Dong-Joo and Lee, Yongseok and Park, Byeong-Gon and Pogge, Richard W. and Penny, Matthew T. and Mao, Shude and Fouqué, Pascal and Wang, Tianshu (2019) KMT-2017-BLG-0165Lb: A Super-Neptune-mass Planet Orbiting a Sun-like Host Star. Astronomical Journal, 157 (2). Art. No. 72. ISSN 1538-3881.

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We report the discovery of a low-mass-ratio planet (q = 1.3 × 10^(−4)), i.e., 2.5 times higher than the Neptune/Sun ratio. The planetary system was discovered from the analysis of the KMT-2017-BLG-0165 microlensing event, which has an obvious short-term deviation from the underlying light curve produced by the host of the planet. Although the fit improvement with the microlens parallax effect is relatively low, one component of the parallax vector is strongly constrained from the light curve, making it possible to narrow down the uncertainties of the lens physical properties. A Bayesian analysis yields that the planet has a super-Neptune mass (M_2 = 34^(+15)_(-12) M⊕) orbiting a Sun-like star (M_1 = 0.76^(+0.34)_(-0.27) M⊙) located at 4.5 kpc. The blended light is consistent with these host properties. The projected planet-host separation is a⊥ = 3.45^(+0.98)_(-0.95) au, implying that the planet is located outside the snow line of the host, i.e., a_(sl) ~ 2.1 au. KMT-2017-BLG-0165Lb is the sixteenth microlensing planet with mass ratio q < 3 × 10^(−4). Using the fifteen of these planets with unambiguous mass-ratio measurements, we apply a likelihood analysis to investigate the form of the mass-ratio function in this regime. If we adopt a broken power law for the form of this function, then the break is at q_(br) ≃ 0.55 × 10^(−4), which is much lower than previously estimated. Moreover, the change of the power-law slope, ζ > 3.3, is quite severe. Alternatively, the distribution is also suggestive of a pileup of planets at Neptune-like mass ratios, below which there is a dramatic drop in frequency.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Jung, Youn Kil0000-0002-0314-6000
Zang, Weicheng0000-0001-6000-3463
Hwang, Kyu-Ha0000-0002-9241-4117
Ryu, Yoon-Hyun0000-0001-9823-2907
Han, Cheongho0000-0002-2641-9964
Yee, Jennifer C.0000-0001-9481-7123
Albrow, Michael D.0000-0003-3316-4012
Chung, Sun-Ju0000-0001-6285-4528
Shin, In-Gu0000-0002-4355-9838
Shvartzvald, Yossi0000-0003-1525-5041
Zhu, Wei0000-0003-4027-4711
Kim, Hyoun-Woo0000-0001-8263-1006
Pogge, Richard W.0000-0003-1435-3053
Penny, Matthew T.0000-0001-7506-5640
Mao, Shude0000-0001-8317-2788
Additional Information:© 2019 The American Astronomical Society. Received 2018 September 4; revised 2018 December 12; accepted 2018 December 12; published 2019 January 25. 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. This research uses data obtained through the Telescope Access Program (TAP), which has been funded by the National Astronomical Observatories of China, the Chinese Academy of Sciences (the Strategic Priority Research Program "The Emergence of Cosmological Structures" grant No. XDB09000000), and the Special Fund for Astronomy from the Ministry of Finance. This work was partly supported by the National Science Foundation of China (grant No. 11333003, 11390372, and 11761131004 to S.M.). This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. C.H. was supported by grant 2017R1A4A1015178 of the National Research Foundation of Korea. Work by A.G. were supported by AST-1516842 from the US NSF. A.G. was supported by JPL grant 1500811. A.G. is supported from KASI grant 2016-1-832-01. A.G. received support from the European Research Council under the European Union's Seventh Framework Programme (FP 7) ERC Grant Agreement no. [321035]. Work by M.T.P. was partially supported by NASA grants NNX16AC62G and NNG16PJ32C.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
National Astronomical Observatories of ChinaUNSPECIFIED
Chinese Academy of SciencesXDB09000000
Ministry of Finance (China)UNSPECIFIED
National Natural Science Foundation of China11333003
National Natural Science Foundation of China11390372
National Natural Science Foundation of China11761131004
National Research Foundation of Korea2017R1A4A1015178
Korea Astronomy and Space Science Institute (KASI)2016-1-832-01
European Research Council (ERC)321035
Subject Keywords:binaries: general – gravitational lensing: micro – planetary systems
Record Number:CaltechAUTHORS:20190125-144959407
Persistent URL:
Official Citation:Youn Kil Jung et al 2019 AJ 157 72
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92481
Deposited By: Tony Diaz
Deposited On:29 Jan 2019 18:01
Last Modified:29 Jan 2019 18:01

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