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  • MOA-2011-BLG-322Lb: a 'seco...
    Shvartzvald, Y; Maoz, D; Kaspi, S; Sumi, T; Udalski, A; Gould, A; Bennett, D. P; Han, C; Abe, F; Bond, I. A; Botzler, C. S; Freeman, M; Fukui, A; Fukunaga, D; Itow, Y; Koshimoto, N; Ling, C. H; Masuda, K; Matsubara, Y; Muraki, Y; Namba, S; Ohnishi, K; Rattenbury, N. J; Saito, To; Sullivan, D. J; Sweatman, W. L; Suzuki, D; Tristram, P. J; Wada, K; Yock, P. C. M; Skowron, J; Koz owski, S; Szyma ski, M. K; Kubiak, M; Pietrzy ski, G; Soszy ski, I; Ulaczyk, K; Wyrzykowski, .; Poleski, R; Pietrukowicz, P

    Monthly Notices of the Royal Astronomical Society, 03/2014, Letnik: 439, Številka: 1
    Journal Article

    Global 'second-generation' microlensing surveys aim to discover and characterize extrasolar planets and their frequency, by means of round-the-clock high-cadence monitoring of a large area of the Galactic bulge, in a controlled experiment. We report the discovery of a giant planet in microlensing event MOA-2011-BLG-322. This moderate-magnification event, which displays a clear anomaly induced by a second lensing mass, was inside the footprint of our second-generation microlensing survey, involving MOA, OGLE and the Wise Observatory. The event was observed by the survey groups, without prompting alerts that could have led to dedicated follow-up observations. Fitting a microlensing model to the data, we find that the time-scale of the event was t E = 23.2 ± 0.8 d, and the mass ratio between the lens star and its companion is q = 0.028 ± 0.001. Finite-source effects are marginally detected, and upper limits on them help break some of the degeneracy in the system parameters. Using a Bayesian analysis that incorporates a Galactic structure model, we estimate the mass of the lens at , at a distance of 7.56 ± 0.91 kpc. Thus, the companion is likely a planet of mass , at a projected separation of au, rather far beyond the snow line. This is the first pure-survey planet reported from a second-generation microlensing survey, and shows that survey data alone can be sufficient to characterize a planetary model. With the detection of additional survey-only planets, we will be able to constrain the frequency of extrasolar planets near their systems' snow lines.