학술논문
OGLE-2018-BLG-1185b : A Low-Mass Microlensing Planet Orbiting a Low-Mass Dwarf
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Working Paper
Author
Kondo, Iona; Yee, Jennifer C.; Bennett, David P.; Sumi, Takahiro; Koshimoto, Naoki; Bond, Ian A.; Gould, Andrew; Udalski, Andrzej; Shvartzvald, Yossi; Jung, Youn Kil; Zang, Weicheng; Bozza, Valerio; Bachelet, Etienne; Hundertmark, Markus P. G.; Rattenbury, Nicholas J.; Abe, F.; Barry, R.; Bhattacharya, A.; Donachie, M.; Fukui, A.; Fujii, H.; Hirao, Y.; Silva, S. Ishitani; Itow, Y.; Kirikawa, R.; Li, M. C. A.; Matsubara, Y.; Miyazaki, S.; Muraki, Y.; Olmschenk, G.; Ranc, C.; Satoh, Y.; Shoji, H.; Suzuki, D.; Tanaka, Y.; Tristram, P. J.; Yamawaki, T.; Yonehara, A.; Mróz, P.; Poleski, R.; Skowron, J.; Szymański, M. K.; Soszyński, I.; Kozłowski, S.; Ulaczyk, P. Pietrukowicz K.; Rybicki, K. A.; Iwanek, P.; Wrona, M.; Albrow, M. D.; Chung, S. -J.; Han, C.; Hwang, K. -H.; Kim, H. -W.; Shin, I. -G.; Cha, S. -M.; Kim, D. -J.; Kim, S. -L.; Lee, C. -U.; Lee, D. -J.; Lee, Y.; Park, B. -G.; Pogge, R. W.; Ryu, Y. -H.; Beichman, C. A.; Bryden, G.; Novati, S. Calchi; Carey, S.; Gaudi, B. S.; Henderson, C. B.; Zhu, W.; Maoz, D.; Penny, M. T.; Dominik, M.; Jørgensen, U. G.; n}}a, P. Longa-Pe{\~{; Peixinho, N.; Sajadian, S.; Skottfelt, J.; Snodgrass, C.; Tregloan-Reed, J.; Burgdorf, M. J.; Campbell-White, J.; Dib, S.; Fujii, Y. I.; Hinse, T. C.; Khalouei, E.; Rahvar, S.; Rabus, M.; Southworth, J.; Tsapras, Y.; Street, R. A.; Bramich, D. M.; Cassan, A.; Horne, K.; Wambsganss, J.; Mao, S.; Saha, A.
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Abstract
We report the analysis of planetary microlensing event OGLE-2018-BLG-1185, which was observed by a large number of ground-based telescopes and by the $Spitzer$ Space Telescope. The ground-based light curve indicates a low planet-host star mass ratio of $q = (6.9 \pm 0.2) \times 10^{-5}$, which is near the peak of the wide-orbit exoplanet mass-ratio distribution. We estimate the host star and planet masses with a Bayesian analysis using the measured angular Einstein radius under the assumption that stars of all masses have an equal probability to host this planet. The flux variation observed by $Spitzer$ was marginal, but still places a constraint on the microlens parallax. Imposing a conservative constraint that this flux variation should be $\Delta f_{\rm Spz} < 4$ instrumental flux units indicates a host mass of $M_{\rm host} = 0.37^{+0.35}_{-0.21}\ M_\odot$ and a planet mass of $m_{\rm p} = 8.4^{+7.9}_{-4.7}\ M_\oplus$. A Bayesian analysis including the full parallax constraint from $Spitzer$ suggests smaller host star and planet masses of $M_{\rm host} = 0.091^{+0.064}_{-0.018}\ M_\odot$ and $m_{\rm p} = 2.1^{+1.5}_{-0.4}\ M_\oplus$, respectively. Future high-resolution imaging observations with $HST$ or ELTs could distinguish between these two scenarios and help to reveal the planetary system properties in more detail.
Comment: 30 pages, 11 figures, 5 tables, Accepted for publication in Astronomical Journal (AJ)
Comment: 30 pages, 11 figures, 5 tables, Accepted for publication in Astronomical Journal (AJ)