KMT-2023-BLG-2669: Ninth Free-floating Planet Candidate with $θ_{\rm E}$ measurements

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Hauptverfasser: Jung, Youn Kil, Hwang, Kyu-Ha, Yang, Hongjing, Gould, Andrew, Yee, Jennifer C., Han, Cheongho, Albrow, Michael D., Chung, Sun-Ju, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Seung-Lee, Lee, Chung-Uk, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W.
Format: Preprint
Veröffentlicht: 2024
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author Jung, Youn Kil
Hwang, Kyu-Ha
Yang, Hongjing
Gould, Andrew
Yee, Jennifer C.
Han, Cheongho
Albrow, Michael D.
Chung, Sun-Ju
Ryu, Yoon-Hyun
Shin, In-Gu
Shvartzvald, Yossi
Zang, Weicheng
Cha, Sang-Mok
Kim, Dong-Jin
Kim, Seung-Lee
Lee, Chung-Uk
Lee, Dong-Joo
Lee, Yongseok
Park, Byeong-Gon
Pogge, Richard W.
author_facet Jung, Youn Kil
Hwang, Kyu-Ha
Yang, Hongjing
Gould, Andrew
Yee, Jennifer C.
Han, Cheongho
Albrow, Michael D.
Chung, Sun-Ju
Ryu, Yoon-Hyun
Shin, In-Gu
Shvartzvald, Yossi
Zang, Weicheng
Cha, Sang-Mok
Kim, Dong-Jin
Kim, Seung-Lee
Lee, Chung-Uk
Lee, Dong-Joo
Lee, Yongseok
Park, Byeong-Gon
Pogge, Richard W.
contents 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 $M = 8\,M_{\oplus} (π_{\rm rel} / 0.1\,{\rm mas})^{-1}$, 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 \citealt{gould22}) 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".
format Preprint
id arxiv_https___arxiv_org_abs_2405_16857
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle KMT-2023-BLG-2669: Ninth Free-floating Planet Candidate with $θ_{\rm E}$ measurements
Jung, Youn Kil
Hwang, Kyu-Ha
Yang, Hongjing
Gould, Andrew
Yee, Jennifer C.
Han, Cheongho
Albrow, Michael D.
Chung, Sun-Ju
Ryu, Yoon-Hyun
Shin, In-Gu
Shvartzvald, Yossi
Zang, Weicheng
Cha, Sang-Mok
Kim, Dong-Jin
Kim, Seung-Lee
Lee, Chung-Uk
Lee, Dong-Joo
Lee, Yongseok
Park, Byeong-Gon
Pogge, Richard W.
Earth and Planetary Astrophysics
Astrophysics of Galaxies
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 $M = 8\,M_{\oplus} (π_{\rm rel} / 0.1\,{\rm mas})^{-1}$, 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 \citealt{gould22}) 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".
title KMT-2023-BLG-2669: Ninth Free-floating Planet Candidate with $θ_{\rm E}$ measurements
topic Earth and Planetary Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2405.16857