Year: 2018
Type: article
Abstract: We report on the analysis of a microlensing event, OGLE-2014-BLG-1722, that showed two distinct short-term anomalies. The best-fit model to the observed light curves shows that the two anomalies are explained with two planetary mass ratio companions to the primary lens. Although a binary-source model is also able to explain the second anomaly, it is marginally ruled out by 3.1σ. The two-planet model indicates that the first anomaly was caused by planet “b” with a mass ratio of and projected separation in units of the Einstein radius, s = 0.753 ± 0.004. The second anomaly reveals planet “c” with a mass ratio of with Δχ 2 ∼ 170 compared to the single-planet model. Its separation has two degenerated solutions: the separation of planet c is s 2 = 0.84 ± 0.03 and 1.37 ± 0.04 for the close and wide models, respectively. Unfortunately, this event does not show clear finite-source and microlensing parallax effects; thus, we estimated the physical parameters of the lens system from Bayesian analysis. This gives the masses of planets b and c as and , respectively, and they orbit a late-type star with a mass of located at from us. The projected distances between the host and planets are for planet b and and for the close and wide models of planet c. If the two-planet model is true, then this is the third multiple-planet system detected using the microlensing method and the first multiple-planet system detected in low-magnification events, which are dominant in the microlensing survey data. The occurrence rate of multiple cold gas giant systems is estimated using the two such detections and a simple extrapolation of the survey sensitivity of the 6 yr MOA microlensing survey combined with the 4 yr μFUN detection efficiency. It is estimated that 6% ± 2% of stars host two cold giant planets.
Source: The Astronomical Journal
Authors: D. Suzuki, D. P. Bennett, A. Udalski, I. A. Bond, T. Sumi, C. Han, Ho-il. Kim, F. Abe, Y. Asakura, R. K. Barry, A. Bhattacharya, M. Donachie, M. Freeman, A. Fukui, Y. Hirao, Y. Itow, N. Koshimoto, M. C. A. Li, C. H. Ling, K. Masuda, Y. Matsubara, Y. Muraki, M. Nagakane, K. Onishi, H. Oyokawa, C. Ranc, N. J. Rattenbury, To. Saito, A. Sharan, D. J. Sullivan, P. J. Tristram, A. Yonehara, R. Poleski, P. Mróz, J. Skowron, M. K. Szymański, I. Soszyński, S. Kozłowski, P. Pietrukowicz, Ł. Wyrzykowski, K. Ulaczyk
Institutions: Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Goddard Space Flight Center, University of Maryland, College Park, University of Warsaw, Massey University, The University of Osaka, Chungbuk National University, Korea Astronomy and Space Science Institute, Institute for Space-Earth Environmental Research, Nagoya University, Nagoya University, University of Auckland, National Astronomical Observatory of Japan, National Institute of Technology, Nagano College, Tokyo Metropolitan College of Industrial Technology, Victoria University of Wellington, University of Canterbury, Kyoto Sangyo University, The Ohio State University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: 重力マイクロレンズ法による惑星存在率の銀河系内分布及び主星質量依存性の推定, Microlensing Survey for Exoplanets beyond the Snow Line, G5150637781, Search for extrasolar planets with microlensing, Warwick Astronomy and Astrophysics Consolidated Grant 2017-2020, G6996030003, 世界初の近赤外線による重力マイクロレンズ法を用いた系外惑星探査, Search for cold exoplanets and free-floating planets by near infrared gravitational microlensing observation, G7558095811
OpenAlex ID: W2789728999