Satoh YKKoshimoto NBennett DPSumi TRattenbury NJSuzuki DMiyazaki SBond IAUdalski AGould ABozza VDominik MHirao YKondo IKirikawa RHamada RAbe FBarry RBhattacharya AFujii HFukui AFujita KIkeno TIshitani Silva SItow YMatsubara YMatsumoto SMuraki YNiwa KOkamura AOlmschenk GRanc CToda TTomoyoshi MTristram PJVandorou AYama HYamashita KMróz PPoleski RSkowron JSzymański MKPoleski RSoszyński IPietrukowicz PKozłowski SUlaczyk KRybicki KAIwanek PWrona MGromadzki MAlbrow MDChung S-JHan CHwang K-HKim DJung YKKim HWRyu Y-HShin I-GShvartzvald YYang HYee JCZang WCha S-MKim D-JKim S-LLee C-ULee D-JLee YPark B-GPogge RWJørgensen UGLonga-Peña PSajadian SSkottfelt JSnodgrass CTregloan-Reed JBach-Møller NBurgdorf MD'Ago GHaikala LHitchcock JHundertmark MKhalouei EPeixinho NRahvar SSouthworth JSpyratos P2024-05-082024-05-082023-08-18Satoh YK, Koshimoto N, Bennett DP, Sumi T, Rattenbury NJ, Suzuki D, Miyazaki S, Bond IA, Udalski A, Gould A, Bozza V, Dominik M, Hirao Y, Kondo I, Kirikawa R, Hamada R, Abe F, Barry R, Bhattacharya A, Fujii H, Fukui A, Fujita K, Ikeno T, Ishitani Silva S, Itow Y, Matsubara Y, Matsumoto S, Muraki Y, Niwa K, Okamura A, Olmschenk G, Ranc C, Toda T, Tomoyoshi M, Tristram PJ, Vandorou A, Yama H, Yamashita K, Mróz P, Poleski R, Skowron J, Szymański MK, Poleski R, Soszyński I, Pietrukowicz P, Kozłowski S, Ulaczyk K, Rybicki KA, Iwanek P, Wrona M, Gromadzki M, Albrow MD, Chung SJ, Han C, Hwang KH, Kim D, Jung YK, Kim HW, Ryu YH, Shin IG, Shvartzvald Y, Yang H, Yee JC, Zang W, Cha SM, Kim DJ, Kim SL, Lee CU, Lee DJ, Lee Y, Park BG, Pogge RW, Jørgensen UG, Longa-Peña P, Sajadian S, Skottfelt J, Snodgrass C, Tregloan-Reed J, Bach-Møller N, Burgdorf M, D'Ago G, Haikala L, Hitchcock J, Hundertmark M, Khalouei E, Peixinho N, Rahvar S, Southworth J, Spyratos P. (2023). OGLE-2019-BLG-0825: Constraints on the Source System and Effect on Binary-lens Parameters Arising from a Five-day Xallarap Effect in a Candidate Planetary Microlensing Event. Astronomical Journal. 166. 3.0004-6256https://mro.massey.ac.nz/handle/10179/69521We present an analysis of microlensing event OGLE-2019-BLG-0825. This event was identified as a planetary candidate by preliminary modeling. We find that significant residuals from the best-fit static binary-lens model exist and a xallarap effect can fit the residuals very well and significantly improves χ 2 values. On the other hand, by including the xallarap effect in our models, we find that binary-lens parameters such as mass ratio, q, and separation, s, cannot be constrained well. However, we also find that the parameters for the source system such as the orbital period and semimajor axis are consistent between all the models we analyzed. We therefore constrain the properties of the source system better than the properties of the lens system. The source system comprises a G-type main-sequence star orbited by a brown dwarf with a period of P ∼5 days. This analysis is the first to demonstrate that the xallarap effect does affect binary-lens parameters in planetary events. It would not be common for the presence or absence of the xallarap effect to affect lens parameters in events with long orbital periods of the source system or events with transits to caustics, but in other cases, such as this event, the xallarap effect can affect binary-lens parameters.(c) The author/shttps://creativecommons.org/licenses/by/4.0/Brown dwarfsGravitational microlensingXallarapJournal article10.3847/1538-3881/ace9081538-3881CC BY 4.0journal-article116