MOA-2007-BLG-400 A Super-Jupiter Mass Planet Orbiting a Galactic BulgeK-dwarf Revealed by Keck Adaptive Optics Imaging

Abstract

We present Keck/NIRC2 adaptive optics imaging of planetary microlensing event MOA-2007-BLG-400 that resolves the lens star system from the source. We find that the MOA-2007-BLG-400L planetary system consists of a $1.71\pm 0.27M_{\mathrm{Jup}}$ planet orbiting a $0.69\pm 0.04M_{\odot }$ K-dwarf host star at a distance of $6.89\pm 0.77$kpc from the Sun. So, this planetary system probably resides in the Galactic bulge. The planet-host star projected separation is only weakly constrained due to the close-wide light curve degeneracy; the 2$\sigma$ projected separation range is 0.6--$7.2$AU. This host mass is at the top end of the range of masses predicted by a standard Bayesian analysis that assumes that all stars have an equal chance of hosting a star of the observed mass ratio. This and the similar result for event MOA-2013-BLG-220 suggests that more massive stars may be more likely to host planets with a mass ratio in the $0.002<q<0.004$ range that orbit beyond the snow line. These results also indicate the importance of host star mass measurements for exoplanets found by microlensing. The microlensing survey imaging data from NASA's Nancy Grace Roman Space Telescope (formerly WFIRST) mission will be doing mass measurements like this for a huge number of planetary events. This host lens is the highest contrast lens-source detected in microlensing mass measurement analysis (the lens being 10$\times$ fainter than the source). We present an improved method of calculating photometry and astrometry uncertainties based on the Jackknife method, which produces more accurate errors that are $\sim$$2.5\times$ larger than previous estimates.

29 pages, 4 figures, AJ submitted

References in corpus (15)

• Planet formation around stars of various masses: The snow line and the frequency of giant planets
• Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing
• A New Planet Around an M Dwarf: Revealing a Correlation Between Exoplanets and Stellar Mass
• The Exoplanet Mass-Ratio Function from the MOA-II Survey: Discovery of a Break and Likely Peak at a Neptune Mass
• Hints for a Turnover at the Snow Line in the Giant Planet Occurrence Rate
• Spitzer as Microlens Parallax Satellite: Mass Measurement for the OGLE-2014-BLG-0124L Planet and its Host Star
• Identification of the OGLE-2003-BLG-235/MOA-2003-BLG-53 Planetary Host Star
• Cool Jupiters greatly outnumber their toasty siblings: Occurrence rates from the Anglo-Australian Planet Search
• Synthesizing Exoplanet Demographics from Radial Velocity and Microlensing Surveys, II: The Frequency of Planets Orbiting M Dwarfs
• Planetary and Other Short Binary Microlensing Events from the MOA Short Event Analysis
• Microlensing Results Challenge the Core Accretion Runaway Growth Scenario for Gas Giants
• Synthesizing Exoplanet Demographics from Radial Velocity and Microlensing Surveys, I: Methodology
• A Gas Giant Planet in the OGLE-2006-BLG-284L Stellar Binary System
• Application of a new method to study the spin equilibrium of Aql X-1: the possibility of gravitational radiation
• Pixel Level Decorrelation in Service of the \textit{Spitzer} Microlens Parallax Survey

Cited by in corpus (12)

• RV-detected planets around M dwarfs: Challenges for core accretion models
• Euclid-Roman joint microlensing survey: early mass measurement, free floating planets and exomoons
• No Large Dependence of Planet Frequency on Galactocentric Distance
• Free-floating or wide-orbit? Keck adaptive-optics observations of free-floating planet candidates detected with gravitational microlensing
• Unveiling MOA-2007-BLG-192: An M Dwarf Hosting a Likely Super-Earth
• Confirmation of Color Dependent Centroid Shift Measured After 1.8 years with HST
• OGLE-2016-BLG-1093Lb: A Sub-Jupiter-mass Spitzer Planet Located in Galactic Bulge
• A Candidate High-Velocity Exoplanet System in the Galactic Bulge
• MOA-2020-BLG-208Lb: Cool Sub-Saturn Planet Within Predicted Desert
• MOA-2010-BLG-328: Keck and HST Expose the Limits of Occams Razor in Microlensing
• Constraining Lens Masses in Moderately to Highly Magnified Microlensing Events from Gaia
• MOA-2020-BLG-135Lb: A New Neptune-class Planet for the Extended MOA-II Exoplanet Microlens Statistical Analysis