KMT-2018-BLG-1988Lb: microlensing super-Earth orbiting a low-mass disk dwarf

Abstract

We reexamine high-magnification microlensing events in the previous data collected by the KMTNet survey with the aim of finding planetary signals that were not noticed before. In this work, we report the planetary system KMT-2018-BLG-1988L that was found from this investigation. The planetary signal appears as a deviation with $\lesssim 0.2$~mag from a single-lens light curve and lasted for about 6 hours. The deviation exhibits a pattern of a dip surrounded by weak bumps on both sides of the dip. The analysis of the lensing light curve indicates that the signal is produced by a low mass-ratio ($q\sim 4\times 10^{-5}$) planetary companion located near the Einstein ring of the host star. The mass of the planet, $M_{\mathrm{planet}}=6.8_{-3.5}^{+4.7}{M}_{\oplus }$ and $5.6_{-2.8}^{+3.8}{M}_{\oplus }$ for the two possible solutions, estimated from the Bayesian analysis indicates that the planet is in the regime of a super-Earth. The host of the planet is a disk star with a mass of $M_{\mathrm{host}}=0.47_{-0.25}^{+0.33}{M}_{\odot }$ and a distance of $D_{\mathrm{L}}=4.2_{-.14}^{+1.8}$~kpc. KMT-2018-BLG-1988Lb is the seventeenth microlensing planet with a mass below the upper limit of a super-Earth. The fact that 14 out of 17 microlensing planets with masses $\lesssim 10M_{\oplus }$ were detected during the last 5 years since the full operation of the KMTNet survey indicates that the KMTNet database is an important reservoir of very low-mass planets.

arXiv comment8 pages, 7 figures

References in corpus (41)

• A method for optimal image subtraction
• Discovery of a Cool Planet of 5.5 Earth Masses Through Gravitational Microlensing
• 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
• Frequency of Solar-Like Systems and of Ice and Gas Giants Beyond the Snow Line from High-Magnification Microlensing Events in 2005-2008
• A Low-Mass Planet with a Possible Sub-Stellar-Mass Host in Microlensing Event MOA-2007-BLG-192
• 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
• Radius and Structure models for the First Super-Earth Planet
• MOA-2011-BLG-293Lb: A test of pure survey microlensing planet detections
• Stellar Contribution to the Galactic Bulge Microlensing Optical Depth
• MOA-2009-BLG-387Lb: A massive planet orbiting an M dwarf
• The Mass Spectrum Of Machos From Parallax Measurements
• Planet Parameters in Microlensing Events
• Korea Microlensing Telescope Network Microlensing Events from 2015: Event-Finding Algorithm, Vetting, and Photometry
• A Terrestrial Planet in a ~1 AU Orbit Around One Member of a ~15 AU Binary
• Gravitational lens under perturbations: Symmetry of perturbing potentials with invariant caustics
• An Earth-mass Planet in a 1-AU Orbit around an Ultracool Dwarf
• The Lowest Mass Ratio Planetary Microlens: OGLE 2016-BLG-1195Lb
• Predictions for Microlensing Planetary Events from Core Accretion Theory
• A terrestrial-mass rogue planet candidate detected in the shortest-timescale microlensing event
• Systematic KMTNet Planetary Anomaly Search, Paper I: OGLE-2019-BLG-1053Lb, A Buried Terrestrial Planet
• OGLE-2018-BLG-0567Lb and OGLE-2018-BLG-0962Lb: Two Microlensing Planets through Planetary-Caustic Channel
• A Characteristic Planetary Feature in Double-Peaked, High-Magnification Microlensing Events
• Systematic KMTNet Planetary Anomaly Search, Paper II: Six New $q<2\times 10^{-4}$ Mass-ratio Planets
• The Many Possible Interpretations of Microlensing Event OGLE-2002-BLG-055
• Ogle-2018-blg-0677lb: A super earth near the galactic bulge
• OGLE-2015-BLG-1771Lb: A Microlens Planet Orbiting an Ultracool Dwarf?
• Spectroscopic Mass and Host-star Metallicity Measurements for Newly Discovered Microlensing Planet OGLE-2018-BLG-0740Lb
• Microlensing Predictions: Impact of Galactic Disc Dynamical Models
• Three microlensing planets with no caustic-crossing features
• OGLE-2018-BLG-0532Lb: Cold Neptune With Possible Jovian Sibling
• KMT-2019-BLG-0842Lb: A Cold Planet Below the Uranus/Sun Mass Ratio
• KMT-2018-BLG-1025Lb: microlensing super-Earth planet orbiting a low-mass star
• Four Microlensing Planets with Faint-source Stars Identified in the 2016 and 2017 Season Data
• OGLE-2018-BLG-1269Lb: A Jovian Planet With A Bright, $I=16$ Host
• OGLE-2017-BLG-1434Lb: Confirmation of a Cold Super-Earth using Keck Adaptive Optics