Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Microlens OGLE-2005-BLG-169 Implies Cool Neptune-Like Planets are Common   We detect a Neptune mass-ratio (q~8e-5) planetary companion to the lens star
in the extremely high-magnification (A~800) microlensing event
OGLE-2005-BLG-169. If the parent is a main-sequence star, it has mass M~0.5
M_sun implying a planet mass of ~13 M_earth and projected separation of ~2.7
AU. When intensely monitored over their peak, high-magnification events similar
to OGLE-2005-BLG-169 have nearly complete sensitivity to Neptune mass-ratio
planets with projected separations of 0.6 to 1.6 Einstein radii, corresponding
to 1.6--4.3 AU in the present case. Only two other such events were monitored
well enough to detect Neptunes, and so this detection by itself suggests that
Neptune mass-ratio planets are common. Moreover, another Neptune was recently
discovered at a similar distance from its parent star in a low-magnification
event, which are more common but are individually much less sensitive to
planets. Combining the two detections yields 90% upper and lower frequency
limits f=0.37^{+0.30}_{-0.21} over just 0.4 decades of planet-star separation.
In particular, f>16% at 90% confidence. The parent star hosts no Jupiter-mass
companions with projected separations within a factor 5 of that of the detected
planet. The lens-source relative proper motion is \mu~7--10 mas/yr, implying
that if the lens is sufficiently bright, I<23.8, it will be detectable by HST
by 3 years after peak. This would permit a more precise estimate of the lens
mass and distance, and so the mass and projected separation of the planet.
Analogs of OGLE-2005-BLG-169Lb orbiting nearby stars would be difficult to
detect by other methods of planet detection, including radial velocities,
transits, or astrometry.

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The categories of this paper are: alg-geom
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The categories of this paper are: funct-an
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The categories of this paper are: dg-ga
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: cond-mat
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The categories of this paper are: physics
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The categories of this paper are: ao-sci
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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex