Microlensing by a wide-separation planet: detectability and boundness
arXiv:1306.1005 · doi:10.1093/mnras/stt980
Abstract
We explore the detection condition of a wide-separation planet through the perturbation induced by the planetary caustic for various microlensing parameters, especially for the size of the source stars. By constructing the fractional deviation maps at various positions in the space of microlensing parameters, we find that the pattern of the fractional deviation depends on the ratio of the source radius to the caustic size, and the ratio satisfying the observational threshold varies with the star-planet separation. We have also obtained the upper limits of the source size that allows the detection of the signature of the host star as a function of the separation for given observational threshold. It is shown that this relation further leads one to a simple analytic condition for the star-planet separation to detect the boundness of wide-separation planets as a function of the mass ratio and the source radius. For example, when 5% of the detection threshold is assumed, for a source star with the radius of ~1 R_sun, an Earth-mass planet and a Jupiter-mass planet can be recognized of its boundness when it is within the separation range of ~10 AU and ~30 AU, respectively. We also compare the separation ranges of detection by the planetary caustic with those by the central caustic. It is found that when the microlensing light curve caused by the planetary caustic happens to be analyzed, one may afford to support the boundness of the wide-separation planet farther than when that caused by the central caustic is analyzed. Finally, we conclude by briefly discussing the implication of our findings on the next-generation microlensing experiments.
9 pages, 4 figures, accepted for publication in MNRAS
References in corpus (16)
- Unbound or Distant Planetary Mass Population Detected by Gravitational Microlensing
- Planet formation around stars of various masses: The snow line and the frequency of giant planets
- Origins of Eccentric Extrasolar Planets: Testing the Planet-Planet Scattering Model
- Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing
- Microlens OGLE-2005-BLG-169 Implies Cool Neptune-Like Planets are Common
- A Low-Mass Planet with a Possible Sub-Stellar-Mass Host in Microlensing Event MOA-2007-BLG-192
- MOA-2011-BLG-293Lb: A test of pure survey microlensing planet detections
- The Great Escape: How Exoplanets and Smaller Bodies Desert Dying Stars
- MOA-2009-BLG-387Lb: A massive planet orbiting an M dwarf
- Planet-Planet Scattering Alone Cannot Explain the Free-Floating Planet Population
- Discovery and Mass Measurements of a Cold, 10-Earth Mass Planet and Its Host Star
- Planetary and Other Short Binary Microlensing Events from the MOA Short Event Analysis
- The second multiple-planet system discovered by microlensing: OGLE-2012-BLG-0026Lb, c, a pair of jovian planets beyond the snow line
- MOA-2010-BLG-477Lb: constraining the mass of a microlensing planet from microlensing parallax, orbital motion and detection of blended light
- A Giant Planet beyond the Snow Line in Microlensing Event OGLE-2011-BLG-0251
- Characterization of Microlensing Planets with Moderately Wide Separations