OGLE-2017-BLG-0406: ${\it Spitzer}$ Microlens Parallax Reveals Saturn-mass Planet orbiting M-dwarf Host in the Inner Galactic Disk
Creators: name: Hirao, Yuki
name: Bennett, David P.
name: Ryu, Yoon-Hyun
name: Koshimoto, Naoki
name: Udalski, Andrzej
name: Yee, Jennifer C.
name: Sumi, Takahiro
name: Bond, Ian A.
name: Shvartzvald, Yossi
name: Abe, Fumio
name: Barry, Richard K.
name: Bhattacharya, Aparna
name: Donachie, Martin
name: Fukui, Akihiko
name: Itow, Yoshitaka
name: Kondo, Iona
name: Li, Man Cheung Alex
name: Matsubara, Yutaka
name: Matsuo, Taro
name: Miyazaki, Shota
name: Muraki, Yasushi
name: Nagakane, Masayuki
name: Ranc, Clement
name: Rattenbury, Nicholas J.
name: Suematsu, Haruno
name: Shibai, Hiroshi
name: Suzuki, Daisuke
name: Tristram, Paul J.
name: Yonehara, Atsunori
name: Skowron, J.
name: Poleski, R.
name: Mroz, P.
name: Szymanski, M. K.
name: Soszynski, I.
name: Kozlowski, S.
name: Pietrukowicz, P.
name: Ulaczyk, K.
name: Rybicki, K.
name: Iwanek, P.
name: Albrow, Michael D.
name: Chung, Sun-Ju
name: Gould, Andrew
name: Han, Cheongho
name: Hwang, Kyu-Ha
name: Jung, Youn Kil
name: Shin, In-Gu
name: Zang, Weicheng
name: Cha, Sang-Mok
name: Kim, Dong-Jin
name: Kim, Hyoun-Woo
name: Kim, Seung-Lee
name: Lee, Chung-Uk
name: Lee, Dong-Joo
name: Lee, Yongseok
name: Park, Byeong-Gon
name: Pogge, Richard W.
name: Beichman, Charles A.
name: Bryden, Geoffery
name: Novati, Sebastiano Calchi
name: Carey, Sean
name: Gaudi, B. Scott
name: Henderson, Calen B.
name: Zhu, Wei
name: Bachelet, Etienne
name: Bolt, Greg
name: Christie, Grant
name: Hundertmark, Markus
name: Natusch, Tim
name: Maoz, Dan
name: McCormick, Jennie
name: Street, Rachel A.
name: Tan, Thiam-Guan
name: Tsapras, Yiannis
name: Jorgensen, U. G.
name: Dominik, M.
name: Bozza, V.
name: Skottfelt, J.
name: Snodgrass, C.
name: Ciceri, S.
name: Jaimes, R. Figuera
name: Evans, D. F.
name: Peixinho, N.
name: Hinse, T. C.
name: Burgdorf, M. J.
name: Southworth, J.
name: Rahvar, S.
name: Sajadian, S.
name: Rabus, M.
name: von Essen, C.
name: Fujii, Y. I.
name: Campbell-White, J.
name: Lowry, S.
name: Helling, C.
name: Mancini, L.
name: Haikala, L.
name: Kandori, Ryo
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We report the discovery and analysis of the planetary microlensing event OGLE-2017-BLG-0406, which was observed both from the ground and by the ${\it Spitzer}$ satellite in a solar orbit. At high magnification, the anomaly in the light curve was densely observed by ground-based-survey and follow-up groups, and it was found to be explained by a planetary lens with a planet/host mass ratio of $q=7.0 \times 10^{-4}$ from the light-curve modeling. The ground-only and ${\it Spitzer}$-"only" data each provide very strong one-dimensional (1-D) constraints on the 2-D microlens parallax vector $\bf{π_{\rm E}}$. When combined, these yield a precise measurement of $\bf{π_{\rm E}}$, and so of the masses of the host $M_{\rm host}=0.56\pm0.07\,M_\odot$ and planet $M_{\rm planet} = 0.41 \pm 0.05\,M_{\rm Jup}$. The system lies at a distance $D_{\rm L}=5.2 \pm 0.5 \ {\rm kpc}$ from the Sun toward the Galactic bulge, and the host is more likely to be a disk population star according to the kinematics of the lens. The projected separation of the planet from the host is $a_{\perp} = 3.5 \pm 0.3 \ {\rm au}$, i.e., just over twice the snow line. The Galactic-disk kinematics are established in part from a precise measurement of the source proper motion based on OGLE-IV data. By contrast, the ${\it Gaia}$ proper-motion measurement of the source suffers from a catastrophic $10\,σ$ error.
description: 40 pages, 12 figures, 10 tables, accepted for publication in The Astronomical Journal