2024/05/27 by Youn Kil Jung, Jung, Youn Kil, Kyu‐Ha Hwang +37 · 1 citation
Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics of Galaxies (astro-ph.GA) #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Geomagnetism and Paleomagnetism Studies #Geophysics and Gravity Measurements #Solar and Space Plasma Dynamics
paper · pdf · doi:10.48550/arxiv.2405.16857
openalex publication_date 2024/05/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report a free-floating planet (FFP) candidate identified from the analysis of the microlensing event KMT-2023-BLG-2669. The lensing light curve is characterized by a short duration (\lesssim 3 \rm days) and a small amplitude (\lesssim 0.7 \rm mag). From the analysis, we find the Einstein timescale of t\rm E \backsimeq 0.33 \rm days and the Einstein radius of θ\rm E \backsimeq 4.41 μ\rm as. These measurements enable us to infer the lens mass as M = 8 M⊕ (π\rm rel / 0.1 \rm mas)-1, where π\rm rel is the relative lens-source parallax. The inference implies that the lens is a sub-Neptune- to Saturn-mass object depending on its unknown distance. This is the ninth isolated planetary-mass microlens with θ\rm E < 10 μ\rm as, which (as shown by \citealtgould22) is a useful threshold for a FFP candidate. We conduct extensive searches for possible signals of a host star in the light curve, but find no strong evidence for the host. We investigate the possibility of using late-time high-resolution imaging to probe for possible hosts. In particular, we discuss that for the case of finite-source point-lens FFP candidates, it would be possible to search for very wide separation hosts immediately, although such searches are "high-risk, high-reward".