KMT-2023-BLG-2669: Ninth Free-floating Planet Candidate with θ E Measurements

Autor: Youn Kil Jung, Kyu-Ha Hwang, Hongjing Yang, Andrew Gould, Jennifer C. Yee, Cheongho Han, Michael D. Albrow, Sun-Ju Chung, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Weicheng Zang, Sang-Mok Cha, Dong-Jin Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: The Astronomical Journal, Vol 168, Iss 4, p 152 (2024)
Druh dokumentu: article
ISSN: 1538-3881
DOI: 10.3847/1538-3881/ad6b12
Popis: 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 (≲3 days) and a small amplitude (≲0.7 mag). From the analysis, we find an Einstein timescale of t _E ⋍ 0.33 days and an Einstein radius of θ _E ⋍ 4.41 μ as. These measurements enable us to infer the lens mass as $M=8\,{M}_{\oplus }{\left({\pi }_{\mathrm{rel}}/0.1\,\mathrm{mas}\right)}^{-1}$ , where π _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 _E < 10 μ as, which is a useful threshold for an 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 the case of finite-source point-lens FFP candidates, for which it would be possible to search for very-wide-separation hosts immediately, although such searches are “high risk, high reward.”
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