Detection of planets in extremely weak central perturbation microlensing events via next-generation ground-based surveys

Abstract

Even though the recently discovered high-magnification event MOA-2010-BLG-311 had complete coverage over the peak, confident planet detection did not happen due to extremely weak central perturbations (fractional deviations of $\lesssim 2\%$). For confident detection of planets in extremely weak central perturbation (EWCP) events, it is necessary to have both high cadence monitoring and high photometric accuracy better than those of current follow-up observation systems.The next-generation ground-based observation project, KMTNet (Korea Microlensing Telescope Network), satisfies the conditions. We estimate the probability of occurrence of EWCP events with fractional deviations of $\le 2\%$ in high-magnification events and the efficiency of detecting planets in the EWCP events using the KMTNet. From this study, we find that the EWCP events occur with a frequency of $>50\%$ in the case of $\lesssim 100M_{\mathrm{E}}$ planets with separations of $0.2\mathrm{AU}\lesssim d\lesssim 20\mathrm{AU}$. We find that for main-sequence and subgiant source stars, $\gtrsim 1M_{\mathrm{E}}$ planets in EWCP events with the deviations $\le 2\%$ can be detected $>50\%$ in a certain range that changes with the planet mass. However, it is difficult to detect planets in EWCP events of bright stars like giant stars, because it is easy for KMTNet to be saturated around the peak of the events with a constant exposure time. EWCP events are caused by close, intermediate, and wide planetary systems with low-mass planets and close and wide planetary systems with massive planets. Therefore, we expect that a much greater variety of planetary systems than those already detected, which are mostly intermediate planetary systems regardless of the planet mass, will be significantly detected in the near future.

arXiv comment10 pages, 4 figures, accepted by ApJ

References in corpus (27)

• Discovery of a Cool Planet of 5.5 Earth Masses Through Gravitational Microlensing
• The Use of High Magnification Microlensing Events in Discovering Extra-solar Planets
• Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing
• Frequency of Solar-Like Systems and of Ice and Gas Giants Beyond the Snow Line from High-Magnification Microlensing Events in 2005-2008
• Microlens OGLE-2005-BLG-169 Implies Cool Neptune-Like Planets are Common
• A Jovian-mass Planet in Microlensing Event OGLE-2005-BLG-071
• 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
• A Cold Neptune-Mass Planet OGLE-2007-BLG-368Lb: Cold Neptunes Are Common
• First microlens mass measurement: PLANET photometry of EROS BLG-2000-5
• Microlensing Event MOA-2007-BLG-400: Exhuming the Buried Signature of a Cool, Jovian-Mass Planet
• Sub-Saturn Planet MOA-2008-BLG-310Lb: Likely To Be In The Galactic Bulge
• Discovery and Mass Measurements of a Cold, 10-Earth Mass Planet and Its Host Star
• Properties of Central Caustics in Planetary Microlensing
• Planetary and Other Short Binary Microlensing Events from the MOA Short Event Analysis
• Planetary Microlensing at High Magnification
• 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
• Microlensing Discovery of a Population of Very Tight, Very Low-mass Binary Brown Dwarfs
• A sub-Saturn Mass Planet, MOA-2009-BLG-319Lb
• MOA-2010-BLG-328Lb: a sub-Neptune orbiting very late M dwarf ?
• A Super-Jupiter orbiting a late-type star: A refined analysis of microlensing event OGLE-2012-BLG-0406
• Super-massive planets around late-type stars - the case of OGLE-2012-BLG-0406Lb
• The possibility of detecting planets in the Andromeda Galaxy
• MOA-2008-BLG-379Lb: A Massive Planet from a High Magnification Event with a Faint Source
• MOA-2010-BLG-311: A planetary candidate below the threshold of reliable detection
• Characterization of the Resonant Caustic Perturbation

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