OGLE-2018-BLG-1185b : A Low-Mass Microlensing Planet Orbiting a Low-Mass Dwarf. (arXiv:2104.02157v2 [astro-ph.EP] UPDATED)

OGLE-2018-BLG-1185b : A Low-Mass Microlensing Planet Orbiting a Low-Mass Dwarf. (arXiv:2104.02157v2 [astro-ph.EP] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Kondo_I/0/1/0/all/0/1">Iona Kondo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yee_J/0/1/0/all/0/1">Jennifer C. Yee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bennett_D/0/1/0/all/0/1">David P. Bennett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sumi_T/0/1/0/all/0/1">Takahiro Sumi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koshimoto_N/0/1/0/all/0/1">Naoki Koshimoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bond_I/0/1/0/all/0/1">Ian A. Bond</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gould_A/0/1/0/all/0/1">Andrew Gould</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Udalski_A/0/1/0/all/0/1">Andrzej Udalski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shvartzvald_Y/0/1/0/all/0/1">Yossi Shvartzvald</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jung_Y/0/1/0/all/0/1">Youn Kil Jung</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zang_W/0/1/0/all/0/1">Weicheng Zang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bozza_V/0/1/0/all/0/1">Valerio Bozza</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bachelet_E/0/1/0/all/0/1">Etienne Bachelet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hundertmark_M/0/1/0/all/0/1">Markus P.G. Hundertmark</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rattenbury_N/0/1/0/all/0/1">Nicholas J. Rattenbury</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Abe_F/0/1/0/all/0/1">F. Abe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barry_R/0/1/0/all/0/1">R. Barry</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bhattacharya_A/0/1/0/all/0/1">A. Bhattacharya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Donachie_M/0/1/0/all/0/1">M. Donachie</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fukui_A/0/1/0/all/0/1">A. Fukui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fujii_H/0/1/0/all/0/1">H. Fujii</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hirao_Y/0/1/0/all/0/1">Y. Hirao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Silva_S/0/1/0/all/0/1">S. Ishitani Silva</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Itow_Y/0/1/0/all/0/1">Y. Itow</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kirikawa_R/0/1/0/all/0/1">R. Kirikawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_M/0/1/0/all/0/1">M. C. A. Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsubara_Y/0/1/0/all/0/1">Y. Matsubara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miyazaki_S/0/1/0/all/0/1">S. Miyazaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Muraki_Y/0/1/0/all/0/1">Y. Muraki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Olmschenk_G/0/1/0/all/0/1">G. Olmschenk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ranc_C/0/1/0/all/0/1">C. Ranc</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Satoh_Y/0/1/0/all/0/1">Y. Satoh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shoji_H/0/1/0/all/0/1">H. Shoji</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Suzuki_D/0/1/0/all/0/1">D. Suzuki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tanaka_Y/0/1/0/all/0/1">Y. Tanaka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tristram_P/0/1/0/all/0/1">P. J. Tristram</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yamawaki_T/0/1/0/all/0/1">T. Yamawaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yonehara_A/0/1/0/all/0/1">A. Yonehara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mroz_P/0/1/0/all/0/1">P. Mróz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Poleski_R/0/1/0/all/0/1">R. Poleski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Skowron_J/0/1/0/all/0/1">J. Skowron</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Szymanski_M/0/1/0/all/0/1">M. K. Szymański</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Soszynski_I/0/1/0/all/0/1">I. Soszyński</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kozlowski_S/0/1/0/all/0/1">S. Kozłowski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ulaczyk_P/0/1/0/all/0/1">P. Pietrukowicz K. Ulaczyk</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rybicki_K/0/1/0/all/0/1">K. A. Rybicki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Iwanek_P/0/1/0/all/0/1">P. Iwanek</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wrona_M/0/1/0/all/0/1">M. Wrona</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Albrow_M/0/1/0/all/0/1">M. D. Albrow</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chung_S/0/1/0/all/0/1">S.-J. Chung</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Han_C/0/1/0/all/0/1">C. Han</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hwang_K/0/1/0/all/0/1">K.-H. Hwang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_H/0/1/0/all/0/1">H.-W. Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shin_I/0/1/0/all/0/1">I.-G. Shin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cha_S/0/1/0/all/0/1">S.-M. Cha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_D/0/1/0/all/0/1">D.-J. Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_S/0/1/0/all/0/1">S.-L. Kim</a>, et al. (40 additional authors not shown)

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.

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