MOA-2011-BLG-322

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MOA-2011-BLG-322

Post by Sirius_Alpha on 1st October 2013, 8:41 pm

Looks like we've finally found a planet using just survey techniques instead of alerting other telescopes to observe. And as a result, the author list hasn't pushed the abstract down to the fourth page.

MOA-2011-BLG-322 - a "second generation survey" microlensing planet
http://arxiv.org/abs/1310.0008

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 only, without prompting alerts that could have led to any dedicated follow-up observations. Fitting a microlensing model to the data, we find that the time scale of the event was t_E=23.4+/-0.9 days, and the mass ratio between the lens star and its companion is q=0.024+/-0.002. 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 0.31 +0.34/-0.17 M_sun, at a distance of 7.74 +0.97/-0.91 kpc. Thus, the companion is likely a planet of mass 7.8 +8.6/-4.3 M_J, at a projected separation of 3.6 +1.5/-1.3 AU, rather far beyond the snow line. This is the first pure-survey planet reported from a second-generation microlensing survey, and shows that the 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.

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Re: MOA-2011-BLG-322

Post by Stalker on 2nd October 2013, 3:49 am

1012 Very Happy 

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Re: MOA-2011-BLG-322

Post by Edasich on 2nd October 2013, 10:09 am

It's Microlensing planet time! Very Happy
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