Abstract

The current studies of microlensing planets are limited by small number statistics. Follow-up observations of highmagnification microlensing events can efficiently form a statistical planetary sample. Since 2020, the Korea Microlensing Telescope Network (KMTNet) and the Las Cumbres Observatory (LCO) global network have been conducting a follow-up program for high-magnification KMTNet events. Here, we report the detection and analysis of a microlensing planetary event, KMT-2023-BLG-1431, for which the subtle (0.05 mag) and short-lived (5 hr) planetary signature was characterized by the follow-up from KMTNet and LCO. A binary-lens single-source (2L1S) analysis reveals a planet/host mass ratio of q = (0.72 ± 0.07) × 10-4, and the single-lens binary-source (1L2S) model is excluded by ΔX2 = 80. A Bayesian analysis using a Galactic model yields estimates of the host star mass of Mhost = 0.57+0.33-0.29 M⊙, the planetary mass of Mplanet = 13.5+8.1-6.8 M⊙, and the lens distance of DL = 6.9+0.8-1.7 kpc. The projected planet-host separation of = a⊥ 2.3+0.5-0.5 au or = a⊥ 3.2+0.7-0.8, subject to the close/wide degeneracy. We also find that without the follow-up data, the survey-only data cannot break the degeneracy of central/resonant caustics and the degeneracy of 2L1S/1L2S models, showing the importance of follow-up observations for current microlensing surveys.

Original languageEnglish
Article number054402
JournalPublications of the Astronomical Society of the Pacific
Volume136
Issue number5
DOIs
StatePublished - 1 May 2024

Funding

FundersFunder number
SAAO
Korea Research Environment Open Network
CTIO
Narodowa Agencja Wymiany Akademickiej
Smithsonian Astrophysical Observatory
Scleroderma Society of Ontario
U.S. Department of Defense
National Research Foundation of Korea2020R1A4A2002885, 2019R1A2C2085965
National Natural Science Foundation of China12133005
Korea Astronomy and Space Science Institute2023-1-832-03
Smithsonian InstitutionAST-2108414
Bloom's Syndrome Foundation2020740
Japan Society for the Promotion of ScienceJP17H02871, JSPS24253004, JSPS15H00781, JSPS23340064, JSPS26247023, JP16H06287
National Science FoundationAST-2050813

    Keywords

    • Gravitational microlensing (672)
    • Gravitational microlensing exoplanet detection (2147)

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