OGLE-2018-BLG-0532Lb: Cold Neptune With Possible Jovian Sibling

Abstract

We report the discovery of the planet OGLE-2018-BLG-0532Lb, with very obvious signatures in the light curve that lead to an estimate of the planet-host mass ratio $q=M_{\mathrm{planet}}/M_{\mathrm{host}}\simeq 1\times 10^{-4}$. Although there are no obvious systematic residuals to this double-lens/single-source (2L1S) fit, we find that ${\chi }^2$ can be significantly improved by adding either a third lens (3L1S, $\Delta {\chi }^2=81$) or second source (2L2S, $\Delta {\chi }^2=65$) to the lens-source geometry. After thorough investigation, we conclude that we cannot decisively distinguish between these two scenarios and therefore focus on the robustly-detected planet. However, given the possible presence of a second planet, we investigate to what degree and with what probability such additional planets may affect seemingly single-planet light curves. Our best estimates for the properties of the lens star and the secure planet are: a host mass $M\sim 0.25M_{\odot }$, system distance $D_L\sim 1$kpc and planet mass $m_{p,1}=8M_{\oplus }$ with projected separation $a_{1,\perp }=1.4$au. However, there is a relatively bright $I=18.6$ (and also relatively blue) star projected within $<50$mas of the lens, and if future high-resolution images show that this is coincident with the lens, then it is possible that it is the lens, in which case, the lens would be both more massive and more distant than the best-estimated values above.

arXiv comment48 pages, 9 figures, 7 tables

References in corpus (59)

• A method for optimal image subtraction
• Reddening and Extinction Toward the Galactic Bulge from OGLE-III: The Inner Milky Way's Rv ~ 2.5 Extinction Curve
• Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. V. Evidence for a wide age distribution and a complex MDF
• The angular size of dwarf stars and subgiants - Surface brightness relations calibrated by interferometry
• OGLE-2003-BLG-262: Finite-Source Effects from a Point-Mass Lens
• 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
• The Exoplanet Mass-Ratio Function from the MOA-II Survey: Discovery of a Break and Likely Peak at a Neptune Mass
• Expanding the Realm of Microlensing Surveys with Difference Image Photometry
• A Natural Formalism for Microlensing
• Difference imaging photometry of blended gravitational microlensing events with a numerical kernel
• Resolution of the MACHO-LMC-5 Puzzle: The Jerk-Parallax Microlens Degeneracy
• The Luminosity Function and Mass Function in the Galactic Bulge
• 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
• OGLE-2005-BLG-071Lb, the Most Massive M-Dwarf Planetary Companion?
• Binary microlensing event OGLE-2009-BLG-020 gives a verifiable mass, distance and orbit predictions
• MOA-2009-BLG-387Lb: A massive planet orbiting an M dwarf
• Masses and Orbital Constraints for the OGLE-2006-BLG-109Lb,c Jupiter/Saturn Analog Planetary System
• Microlensing Event MOA-2007-BLG-400: Exhuming the Buried Signature of a Cool, Jovian-Mass Planet
• FITSH -- a software package for image processing
• Systematic Analysis of 22 Microlensing Parallax Candidates
• Korea Microlensing Telescope Network Microlensing Events from 2015: Event-Finding Algorithm, Vetting, and Photometry
• Acceleration and Parallax Effects in Gravitational Microlensing
• Uncloaking globular clusters in the inner Galaxy
• 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
• Mass and Mass Scalings of Super-Earths
• The First Circumbinary Planet Found by Microlensing: OGLE-2007-BLG-349L(AB)c
• Microlensing by Multiple Planets in High Magnification Events
• A Terrestrial Planet in a ~1 AU Orbit Around One Member of a ~15 AU Binary
• Triple Microlens OGLE-2008-BLG-092L: Binary Stellar System with a Circumprimary Uranus-type Planet
• Microlensing Results Challenge the Core Accretion Runaway Growth Scenario for Gas Giants
• 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 Tight, Low Mass-ratio Planetary-mass Object around an Old, Field Brown Dwarf
• WFIRST Exoplanet Mass Measurement Method Finds a Planetary Mass of $39\pm 8M_{\oplus }$ for OGLE-2012-BLG-0950Lb
• Properties of Microlensing Light Curve Anomalies Induced by Multiple Planets
• MOA 2003-BLG-37: A Bulge Jerk-Parallax Microlens Degeneracy
• The First Neptune Analog or Super-Earth with Neptune-like Orbit: MOA-2013-BLG-605Lb
• Keck Observations Confirm a Super-Jupiter Planet Orbiting M-dwarf OGLE-2005-BLG-071L
• Revisiting MOA 2013 BLG-220L: A Solar-type star with a Cold super-Jupiter Companion
• Degeneracies in triple gravitational microlensing
• A Universal Break in the Planet-to-Star Mass-Ratio Function of Kepler MKG stars
• A sub-Saturn Mass Planet, MOA-2009-BLG-319Lb
• OGLE-2016-BLG-0613LABb: A Microlensing Planet in a Binary System
• KMT-2017-BLG-0165Lb: A Super-Neptune mass planet Orbiting a Sun-like Host Star
• Empirical Study of Simulated Two-planet Microlensing Event
• OGLE-2017-BLG-1434Lb: Eighth q < 1 * 10^-4 Mass-Ratio Microlens Planet Confirms Turnover in Planet Mass-Ratio Function
• OGLE-2015-BLG-1459L: The Challenges of Exo-Moon Microlensing
• Microlens Mass Measurement using Triple-Peak Events
• Measurement of Source Star Colors with the K2C9-CFHT Multi-color Microlensing Survey
• MOA-2013-BLG-220Lb: Massive Planetary Companion to Galactic-Disk Host
• A Likely Detection of a Two-Planet System in a Low Magnification Microlensing Event
• OGLE-2016-BLG-0596Lb: High-Mass Planet From High-Magnification Pure-Survey Microlensing Event
• OGLE-2015-BLG-1670Lb: A Cold Neptune beyond the Snow Line in the Provisional WFIRST Microlensing Survey Field
• Constraint on Additional Planets in Planetary Systems Discovered through the Channel of High-magnification Gravitational Microlensing Events

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• Systematic KMTNet Planetary Anomaly Search, Paper II: Six New $q<2\times 10^{-4}$ Mass-ratio Planets
• Systematic KMTNet Planetary Anomaly Search. V. Complete Sample of 2018 Prime-Field
• Microlensing events indicate that super-Earth exoplanets are common in Jupiter-like orbits
• Systematic KMTNet Planetary Anomaly Search, Paper VII: Complete Sample of $q<10^{-4}$ Planets from the First Four-Year Survey
• KMT-2019-BLG-0842Lb: A Cold Planet Below the Uranus/Sun Mass Ratio
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• KMT-2021-BLG-0240: Microlensing event with a deformed planetary signal
• KMT-2019-BLG-0797: binary-lensing event occurring on a binary stellar system
• Light Curve Calculations for Triple Microlensing Systems
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• KMT-2021-BLG-1122L: The first microlensing triple stellar system
• MOA-2022-BLG-249Lb: Nearby microlensing super-Earth planet detected from high-cadence surveys
• An Earth-mass Planet in a Time of Covid-19: KMT-2020-BLG-0414Lb
• Simulations of Triple Microlensing Events I: Detectability of a scaled Sun-Jupiter-Saturn System
• KMT-2018-BLG-1988Lb: microlensing super-Earth orbiting a low-mass disk dwarf