Hwang_2018_AJ_155_259.pdf (1.87 MB)
OGLE-2015-BLG-1459L: The Challenges of Exo-moon Microlensing
journal contribution
posted on 2019-08-30, 08:43 authored by KH Hwang, A Udalski, IA Bond, MD Albrow, SJ Chung, A Gould, C Han, YK Jung, YH Ryu, IG Shin, JC Yee, W Zhu, SM Cha, DJ Kim, HW Kim, SL Kim, CU Lee, DJ Lee, Y Lee, BG Park, RW Pogge, M Pawlak, R Poleski, MK Szymański, J Skowron, I Soszyński, P Mróz, S Kozłowski, P Pietrukowicz, K Ulaczyk, 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 YoneharaWe show that dense OGLE and KMTNet I-band survey data require four bodies (sources plus lenses) to explain the microlensing light curve of OGLE-2015-BLG-1459. However, these can equally well consist of three lenses and one source (3L1S), two lenses and two sources (2L2S), or one lens and three sources (1L3S). In the 3L1S and 2L2S interpretations, the host is a brown dwarf and the dominant companion is a Neptune-class planet, with the third body (in the 3L1S case) being a Mars-class object that could have been a moon of the planet. In the 1L3S solution, the light curve anomalies are explained by a tight (five stellar radii) low-luminosity binary source that is offset from the principal source of the event by . These degeneracies are resolved in favor of the 1L3S solution by color effects derived from comparison to MOA data, which are taken in a slightly different (R/I) passband. To enable current and future (WFIRST) surveys to routinely characterize exo-moons and distinguish among such exotic systems requires an observing strategy that includes both a cadence faster than 9 minute-1and observations in a second band on a similar timescale.
Funding
Work by K.H.H. was support by KASI grant 2017-1-830-03. 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. Work by C.H. was supported by the grant (2017R1A4A101517) of National Research Foundation of Korea. The OGLE Team thanks Prof. G. Pietrzyński for his contribution to the collection of the OGLE photometric data. The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to AU. The MOA project is supported by JSPS KAKENHI Grant Number JSPS24253004, JSPS26247023, JSPS23340064, JSPS15H00781, and JP16H06287.
History
Citation
Astronomical Journal, 2018, 155 (6)Author affiliation
/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and AstronomyVersion
- VoR (Version of Record)
