Paper

KMT-2018-BLG-0029Lb: A Very Low Mass-Ratio Spitzer Microlens Planet

Gaudi, B Scott, Novati, Sebastiano Calchi, Mao, Shude, Pogge, Richard W, Hyoun-Woo, Kim, Petric, Andreea, Yoon-Hyun, Ryu, Yee, Jennifer C, Jung, Youn Kil, Albrow, Michael D, Zhu, Wei, Chung-Uk, Lee, Sang-Mok Cha, Dong-Jin, Kim, Shvartzvald, Yossi, Gould, Andrew, Zang, Weicheng, Han, Cheongho, Fouqué, Pascal, Seung-Lee, Kim, Dong-Joo, Lee, Lee, Yongseok, Bryden, Geoff, Carey, Sean, Penny, Matthew T, Henderson, Calen B, Sun-Ju, Chung, Park, Byeong-Gon, Shin, In-Gu, Kyu-Ha Hwang, Burdullis, Todd, Beichman, Charles

2019

Overview

At \\(q=1.81\\pm 0.20 \\times 10^{-5}\\), KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio \\(q\\) of any microlensing planet to date by more than a factor of two. Hence, it is the first planet that probes below the apparent \"pile-up\" at \\(q=5\\)--10 \\(\\times 10^{-5}\\). The event was observed by {\\it Spitzer}, yielding a microlens-parallax \\(\\pi_{\\rm E}\\) measurement. Combined with a measurement of the Einstein radius \\(\\theta_{\\rm E}\\) from finite-source effects during the caustic crossings, these measurements imply masses of the host \\(M_{\\rm host}=1.14^{+0.10}_{-0.12}\\, M_\\odot\\) and planet \\(M_{\\rm planet} = 7.59^{+0.75}_{-0.69}\\,M_\\oplus\\), system distance \\(D_L = 3.38^{+0.22}_{-0.26}\\,\\,{\\rm kpc}\\) and projected separation \\(a_\\perp = 4.27^{+0.21}_{-0.23}\\,{\\rm au}\\). The blended light, which is substantially brighter than the microlensed source, is plausibly due to the lens and could be observed at high resolution immediately.

• Publisher: Cornell University Library, arXiv.org
• Subject: Microlenses / Parallax / Planetary probes