We report the results of the statistical analysis of planetary signals discovered in MOA-II microlensing survey alert system events from 2007 to 2012.Recent studies (Clanton & Gaudi 2014a,b;Montet et al. 2014) have compared the exoplanet distribution found by microlensing with the results of RV observations of M-dwarfs and found that the results from both methods are consistent, although the radial velocity is only sensitive to planets of Jupiter-mass or greater beyond the snow line.1 They used 13 high magnification events from 4-years of observations. 2 They used 199 events from 6-years of observations.
We present Keck NIRC2 high angular resolution adaptive optics observations of the microlensing event OGLE-2005-BLG-169Lb, taken 8.21 years after the discovery of this planetary system. For the first time for a microlensing planetary event, the source and the lens are completely resolved, providing a precise measurement of their heliocentric relative proper motion, 7.44 0.17 rel,helio m = mas yr −1 . This confirms and refines the initial model presented in the discovery paper and rules out a range of solutions that were allowed by the microlensing light curve. This is also the first time that parameters derived from a microlensing planetary signal are confirmed, both with the Keck measurements, presented in this paper,and independent measurements obtained with the Hubble Space Telescope in I V , and Bbands, presented in a companion paper. Hence, this new measurement of rel,helio m , as well as the measured brightness of the lens in Hband, enabled the mass and distance of the system to be updated:a Uranus-mass planet (m M 13.2 1.3 p = Å ) orbiting a K5-type main sequence star (M M * 0.65 0.05 = ) separated by a 3.4 0.3 = AU, at the distance D 4.0 0.4 L = kpc from us.
We present Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) observations of the source and lens stars for planetary microlensing event OGLE-2005-BLG-169, which confirm the relative proper motion prediction due to the planetary light curve signal observed for this event. This (and the companion Keck result) provide the first confirmation of a planetary microlensing signal, for which the deviation was only 2%. The follow-up observations determine the flux of the planetary host star in multiple passbands and remove light curve model ambiguity caused by sparse sampling of part of the light curve. This leads to a precise determination of the properties of the OGLE-2005-BLG-169Lb planetary system. Combining the constraints from the microlensing light curve with the photometry and astrometry of the HST/WFC3 data, we find star and planet masses of M * = 0.69 ± 0.02M and m p = 14.1 ± 0.9M ⊕ . The planetary microlens system is located toward the Galactic bulge at a distance of D L = 4.1 ± 0.4 kpc and the projected star-planet separation is a ⊥ = 3.5 ± 0.3 AU, corresponding to a semimajor axis of a = 4.0 +2.2 −0.6 AU.
We present a statistical analysis of the first four seasons from a "second-generation" microlensing survey for extrasolar planets, consisting of near-continuous time coverage of 8 deg 2 of the Galactic bulge by the OGLE, MOA, and Wise microlensing surveys. During this period, 224 microlensing events were observed by all three groups. Over 12% of the events showed a deviation from single-lens microlensing, and for ∼1/3 of those the anomaly is likely caused by a planetary companion. For each of the 224 events we have performed numerical ray-tracing simulations to calculate the detection efficiency of possible companions as a function of companion-to-host mass ratio and separation. Accounting for the detection efficiency, we find that 55 +34 −22 % of microlensed stars host a snowline planet. Moreover, we find that Neptunes-mass planets are ∼ 10 times more common than Jupiter-mass planets. The companion-to-host mass ratio distribution shows a deficit at q ∼ 10 −2 , separating the distribution into two companion populations, analogous to the stellar-companion and planet populations, seen in radial-velocity surveys around solar-like stars. Our survey, however, which probes mainly lower-mass stars, suggests a minimum in the distribution in the super-Jupiter mass range, and a relatively high occurrence of brown-dwarf companions.
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