OGLE-2018-BLG-1185b: A Low-Mass Microlensing Planet Orbiting a Low-Mass Dwarf

MiNDSTEp Collaboration; J. Campbell-White

OGLE-2018-BLG-1185b: A Low-Mass Microlensing Planet Orbiting a Low-Mass Dwarf

MiNDSTEp Collaboration, J. Campbell-White

Physics

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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±0.2)×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 ΔfSpz<4 instrumental flux units indicates a host mass of Mhost=0.37+0.35−0.21 M⊙ and a planet mass of mp=8.4+7.9−4.7 M⊕. A Bayesian analysis including the full parallax constraint from Spitzer suggests smaller host star and planet masses of Mhost=0.091+0.064−0.018 M⊙ and mp=2.1+1.5−0.4 M⊕, 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.

Original language	English
Place of Publication	Cornell University
Publisher	arXiv
Number of pages	30
Publication status	Published - Apr 2021

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@techreport{f9368d6bc69c4120844128f9e0b27878,

title = "OGLE-2018-BLG-1185b: A Low-Mass Microlensing Planet Orbiting a Low-Mass Dwarf",

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±0.2)×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 ΔfSpz<4 instrumental flux units indicates a host mass of Mhost=0.37+0.35−0.21 M⊙ and a planet mass of mp=8.4+7.9−4.7 M⊕. A Bayesian analysis including the full parallax constraint from Spitzer suggests smaller host star and planet masses of Mhost=0.091+0.064−0.018 M⊙ and mp=2.1+1.5−0.4 M⊕, 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. ",

author = "{MiNDSTEp Collaboration} and Iona Kondo and Yee, {Jennifer C.} and Takahiro Sumi and Naoki Koshimoto and Bond, {Ian A.} and Andrew Gould and Andrzej Udalski and Yossi Shvartzvald and Jung, {Youn Kil} and Weicheng Zang and Valerio Bozza and Etienne Bachelet and Hundertmark, {Markus P. G.} and Rattenbury, {Nicholas J.} and F. Abe and R. Barry and A. Bhattacharya and A. Fukui and H. Fujii and Y. Hirao and {Ishitani Silva}, S. and Y. Itow and R. Kirikawa and Li, {M. C. A.} and Y. Matsubara and S. Miyazaki and Y. Muraki and G. Olmschenk and C. Ranc and Y. Satoh and H. Shoji and D. Suzuki and Y. Tanaka and Tristram, {P. J.} and T. Yamawaki and A. Yonehara and P. Mr{\'o}z and R. Poleski and J. Skowron and Szyma{\'n}ski, {M. K.} and I. Soszy{\'n}ski and S. Koz{\l}owski and P. Pietrukowicz and Rybicki, {K. A.} and P. Iwanek and Krzysztof Ulaczyk and M. Wrona and Albrow, {M. D.} and Chung, {S. -J.} and Hwang, {K. -H.} and J. Campbell-White",

year = "2021",

month = apr,

language = "English",

publisher = "arXiv",

type = "WorkingPaper",

institution = "arXiv",

}

TY - UNPB

T1 - OGLE-2018-BLG-1185b

T2 - A Low-Mass Microlensing Planet Orbiting a Low-Mass Dwarf

AU - MiNDSTEp Collaboration

AU - Kondo, Iona

AU - Yee, Jennifer C.

AU - Sumi, Takahiro

AU - Koshimoto, Naoki

AU - Bond, Ian A.

AU - Gould, Andrew

AU - Udalski, Andrzej

AU - Shvartzvald, Yossi

AU - Jung, Youn Kil

AU - Zang, Weicheng

AU - Bozza, Valerio

AU - Bachelet, Etienne

AU - Hundertmark, Markus P. G.

AU - Rattenbury, Nicholas J.

AU - Abe, F.

AU - Barry, R.

AU - Bhattacharya, A.

AU - Fukui, A.

AU - Fujii, H.

AU - Hirao, Y.

AU - Ishitani Silva, S.

AU - Itow, Y.

AU - Kirikawa, R.

AU - Li, M. C. A.

AU - Matsubara, Y.

AU - Miyazaki, S.

AU - Muraki, Y.

AU - Olmschenk, G.

AU - Ranc, C.

AU - Satoh, Y.

AU - Shoji, H.

AU - Suzuki, D.

AU - Tanaka, Y.

AU - Tristram, P. J.

AU - Yamawaki, T.

AU - Yonehara, A.

AU - Mróz, P.

AU - Poleski, R.

AU - Skowron, J.

AU - Szymański, M. K.

AU - Soszyński, I.

AU - Kozłowski, S.

AU - Pietrukowicz, P.

AU - Rybicki, K. A.

AU - Iwanek, P.

AU - Ulaczyk, Krzysztof

AU - Wrona, M.

AU - Albrow, M. D.

AU - Chung, S. -J.

AU - Hwang, K. -H.

AU - Campbell-White, J.

PY - 2021/4

Y1 - 2021/4

N2 - 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±0.2)×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 ΔfSpz<4 instrumental flux units indicates a host mass of Mhost=0.37+0.35−0.21 M⊙ and a planet mass of mp=8.4+7.9−4.7 M⊕. A Bayesian analysis including the full parallax constraint from Spitzer suggests smaller host star and planet masses of Mhost=0.091+0.064−0.018 M⊙ and mp=2.1+1.5−0.4 M⊕, 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.

AB - 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±0.2)×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 ΔfSpz<4 instrumental flux units indicates a host mass of Mhost=0.37+0.35−0.21 M⊙ and a planet mass of mp=8.4+7.9−4.7 M⊕. A Bayesian analysis including the full parallax constraint from Spitzer suggests smaller host star and planet masses of Mhost=0.091+0.064−0.018 M⊙ and mp=2.1+1.5−0.4 M⊕, 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.

UR - https://arxiv.org/abs/2104.02157

M3 - Preprint

BT - OGLE-2018-BLG-1185b

PB - arXiv

CY - Cornell University

ER -

OGLE-2018-BLG-1185b: A Low-Mass Microlensing Planet Orbiting a Low-Mass Dwarf

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