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OGLE-2016-BLG-1190Lb: The First Spitzer Bulge Planet Lies Near the Planet/Brown-dwarf Boundary

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posted on 24.09.2019, 16:22 by YH Ryu, JC Yee, A Udalski, IA Bond, Y Shvartzvald, W Zang, R Figuera Jaimes, UG Jorgensen, W Zhu, CX Huang, YK Jung, MD Albrow, SJ Chung, A Gould, C Han, KH Hwang, IG Shin, SM Cha, DJ Kim, HW Kim, SL Kim, CU Lee, DJ Lee, Y Lee, BG Park, RW Pogge, S Calchi Novati, S Carey, CB Henderson, C Beichman, BS Gaudi, P Mróz, R Poleski, J Skowron, MK Szymański, I Soszyński, S Kozłowski, P Pietrukowicz, K Ulaczyk, M Pawlak, F Abe, Y Asakura, R Barry, DP Bennett, A Bhattacharya, M Donachie, P Evans, A Fukui, Y Hirao, Y Itow, K Kawasaki, N Koshimoto, MCA Li, CH Ling, K Masuda, Y Matsubara, S Miyazaki, Y Muraki, M Nagakane, K Ohnishi, C Ranc, NJ Rattenbury, T Saito, A Sharan, DJ Sullivan, T Sumi, D Suzuki, PJ Tristram, T Yamada, A Yonehara, G Bryden, SB Howell, S Jacklin, MT Penny, S Mao, P Fouqué, T Wang, RA Street, Y Tsapras, M Hundertmark
We report the discovery of OGLE-2016-BLG-1190Lb, which is likely to be the first Spitzer microlensing planet in the Galactic bulge/bar, an assignation that can be confirmed by two epochs of high-resolution imaging of the combined source-lens baseline object. The planet's mass, Mp= 13.4 ± 0.9 MJ, places it right at the deuterium-burning limit, i.e., the conventional boundary between "planets" and "brown dwarfs." Its existence raises the question of whether such objects are really "planets" (formed within the disks of their hosts) or "failed stars" (low-mass objects formed by gas fragmentation). This question may ultimately be addressed by comparing disk and bulge/bar planets, which is a goal of the Spitzer microlens program. The host is a G dwarf, Mhost= 0.89 ± 0.07 Mo, and the planet has a semimajor axis a ∼ 2.0 au. We use Kepler K2 Campaign 9 microlensing data to break the lens-mass degeneracy that generically impacts parallax solutions from Earth-Spitzer observations alone, which is the first successful application of this approach. The microlensing data, derived primarily from near-continuous, ultradense survey observations from OGLE, MOA, and three KMTNet telescopes, contain more orbital information than for any previous microlensing planet, but not quite enough to accurately specify the full orbit. However, these data do permit the first rigorous test of microlensing orbital-motion measurements, which are typically derived from data taken over <1% of an orbital period.


The work by W.Z., Y.K.J., and A.G. were supported by AST-1516842 from the US NSF. W.Z., I.G.S., and A.G. were supported by JPL grant 1500811. 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. The work by C.H. was supported by the grant (2017R1A4A101517) of National Research Foundation of Korea. The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to A.U. The MOA project is supported by JSPS KAKENHI Grant Number JSPS24253004, JSPS26247023, JSPS23340064, JSPS15H00781, and JP16H06287. The work by C.R. was supported by an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by USRA through a contract with NASA. The work by Y.S. was supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, California Institute of Technology, administered by the Universities Space Research Association through a contract with NASA. The United Kingdom Infrared Telescope (UKIRT) is supported by NASA and operated under an agreement among the University of Hawaii, the University of Arizona, and Lockheed Martin Advanced Technology Center; operations are enabled through the cooperation of the Joint Astronomy Centre of the Science and Technology Facilities Council of the UK. We acknowledge the support from NASA HQ for the UKIRT observations in connection with K2 C9. 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. Based on observations obtained with MegaPrime/MegaCam, a joint project of



Astronomical Journal, 2018, 155 (1)

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


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