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Two new free-floating or wide-orbit planets from microlensing

Mróz, Przemek and Shvartzvald, Yossi (2019) Two new free-floating or wide-orbit planets from microlensing. Astronomy and Astrophysics, 622 . Art. No. A201. ISSN 0004-6361.

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Planet formation theories predict the existence of free-floating planets that have been ejected from their parent systems. Although they emit little or no light, they can be detected during gravitational microlensing events. Microlensing events caused by rogue planets are characterized by very short timescales t_E (typically below two days) and small angular Einstein radii θ_E (up to several μas). Here we present the discovery and characterization of two ultra-short microlensing events identified in data from the Optical Gravitational Lensing Experiment (OGLE) survey, which may have been caused by free-floating or wide-orbit planets. OGLE-2012-BLG-1323 is one of the shortest events discovered thus far (t_E = 0.155 ± 0.005 d, θ_E = 2.37 ± 0.10μas) and was caused by an Earth-mass object in the Galactic disk or a Neptune-mass planet in the Galactic bulge. OGLE-2017-BLG-0560 (t_E = 0.905 ± 0.005 d, θ_E = 38.7 ± 1.6μas) was caused by a Jupiter-mass planet in the Galactic disk or a brown dwarf in the bulge. We rule out stellar companions up to a distance of 6.0 and 3.9 au, respectively. We suggest that the lensing objects, whether located on very wide orbits or free-floating, may originate from the same physical mechanism. Although the sample of ultrashort microlensing events is small, these detections are consistent with low-mass wide-orbit or unbound planets being more common than stars in the Milky Way.

Item Type:Article
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URLURL TypeDescription Paper
Mróz, Przemek0000-0001-7016-1692
Shvartzvald, Yossi0000-0003-1525-5041
Additional Information:© 2019 ESO. Article published by EDP Sciences. Received 1 November 2018; Accepted 9 January 2019; Published online 21 February 2019. P.M. acknowledges support from the Foundation for Polish Science (Program START) and the National Science Center, Poland (grant ETIUDA 2018/28/T/ST9/00096). The OGLE project has received funding from the National Science Center, Poland, grant MAESTRO 2014/14/A/ST9/00121 to A.U. Work by A.G. was supported by AST-1516842 from the US NSF. I.G.S. and A.G. were supported 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 n. [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 a grant (2017R1A4A1015178) from the National Research Foundation of Korea. The MOA project is supported by JSPS KAKENHI Grant Numbers JSPS24253004, JSPS26247023, JSPS23340064, JSPS15H00781, and JP16H06287. This research was supported by the I-CORE program of the Planning and Budgeting Committee and the Israel Science Foundation, Grant 1829/12. D.M. and A.G. acknowledge support from the US-Israel Binational Science Foundation.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Foundation for Polish ScienceSTART
National Science Centre (Poland)ETIUDA 2018/28/T/ST9/00096
National Science Centre (Poland)MAESTRO 2014/14/A/ST9/00121
European Research Council (ERC)321035
National Research Foundation of Korea2017R1A4A1015178
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
I-CORE Program of the Planning and Budgeting CommitteeUNSPECIFIED
Israel Science Foundation1829/12
Binational Science Foundation (USA-Israel)UNSPECIFIED
Subject Keywords:planets and satellites: detection – gravitational lensing: micro
Record Number:CaltechAUTHORS:20190307-104221429
Persistent URL:
Official Citation:Two new free-floating or wide-orbit planets from microlensing. The OGLE Collaboration, Przemek Mróz, Andrzej Udalski, David P. Bennett, Yoon-Hyun Ryu, Takahiro Sumi, Yossi Shvartzvald, Jan Skowron, Radosław Poleski, Paweł Pietrukowicz, Szymon Kozłowski, Michał K. Szymański, Łukasz Wyrzykowski, Igor Soszyński, Krzysztof Ulaczyk, Krzysztof Rybicki, Patryk Iwanek, The KMTNet Collaboration, Michael D. Albrow, Sun-Ju Chung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, In-Gu Shin, Jennifer C. Yee, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Hyoun-Woo Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, The MOA Collaboration, Fumio Abe, Richard Barry, Aparna Bhattacharya, Ian A. Bond, Martin Donachie, Akihiko Fukui, Yuki Hirao, Yoshitaka Itow, Kohei Kawasaki, Iona Kondo, Naoki Koshimoto, Man Cheung Alex Li, Yutaka Matsubara, Yasushi Muraki, Shota Miyazaki, Masayuki Nagakane, Clément Ranc, Nicholas J. Rattenbury, Haruno Suematsu, Denis J. Sullivan, Daisuke Suzuki, Paul J. Tristram, Atsunori Yonehara, The Wise Group, Dan Maoz, Shai Kaspi and Matan Friedmann. A&A, 622 (2019) A201. DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:93630
Deposited By: Tony Diaz
Deposited On:07 Mar 2019 21:04
Last Modified:07 Feb 2020 18:53

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