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arXiv · 2205.07522

MOA-2019-BLG-008Lb: a new microlensing detection of an object at the planet/brown dwarf boundary

E. Bachelet·Y. Tsapras·Andrew Gould·R. A. Street·David P. Bennett·M. P. G. Hundertmark·V. Bozza·D. M. Bramich·A. Cassan·M. Dominik·K. Horne·S. Mao·A. Saha·J. Wambsganss·Weicheng Zang·Fumio Abe·Richard Barry·Aparna Bhattacharya·Ian A. Bond·Akihiko Fukui·Hirosane Fujii·Yuki Hirao·Yoshitaka Itow·Rintaro Kirikawa·Naoki Koshimoto·Yutaka Matsubara·Sho Matsumoto·Shota Miyazaki·Yasushi Muraki·Greg Olmschenk·Clément Ranc·Arisa Okamura·Nicholas J. Rattenbury·Yuki Satoh·Takahiro Sumi·Daisuke Suzuki·Stela Ishitani Silva·Taiga Toda·Paul . J. Tristram·Aikaterini Vandorou·Hibiki Yama·Michael D. Albrow·Sun-Ju Chung·Cheongho Han·Kyu-Ha Hwang·Youn Kil Jung·Yoon-Hyun Ryu·In-Gu Shin·Yossi Shvartzvald·Jennifer C. Yee·Sang-Mok Cha·Dong-Jin Kim·Seung-Lee Kim·Chung-Uk Lee·Dong-Joo Lee·Yongseok Lee·Byeong-Gon Park·Richard W. Pogge·Andrzej Udalski·Przemek Mróz·Rados law Poleski·Jan Skowron·Micha l K. Szymański·Igor Soszyński·Pawe l Pietrukowicz·Szymon Kozlowski·Krzysztof Ulaczyk·Krzysztof A. Rybicki·Patryk Iwanek·Marcin Wrona·Mariusz Gromadzki
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Abstract

We report on the observations, analysis and interpretation of the microlensing event MOA-2019- BLG-008. The observed anomaly in the photometric light curve is best described through a binary lens model. In this model, the source did not cross caustics and no finite source effects were observed. Therefore the angular Einstein ring radius cannot be measured from the light curve alone. However, the large event duration, t E about 80 days, allows a precise measurement of the microlensing parallax. In addition to the constraints on the angular radius and the apparent brightness I s of the source, we employ the Besancon and GalMod galactic models to estimate the physical properties of the lens. We find excellent agreement between the predictions of the two Galactic models: the companion is likely a resident of the brown dwarf desert with a mass Mp about 30 MJup and the host is a main sequence dwarf star. The lens lies along the line of sight to the Galactic Bulge, at a distance of less then4 kpc. We estimate that in about 10 years, the lens and source will be separated by 55 mas, and it will be possible to confirm the exact nature of the lensing system by using high-resolution imaging from ground or space-based observatories.

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E. Bachelet, Y. Tsapras, Andrew Gould, R. A. Street, David P. Bennett, M. P. G. Hundertmark, V. Bozza, D. M. Bramich, A. Cassan, M. Dominik, K. Horne, S. Mao, A. Saha, J. Wambsganss, Weicheng Zang, Fumio Abe, Richard Barry, Aparna Bhattacharya, Ian A. Bond, Akihiko Fukui, Hirosane Fujii, Yuki Hirao, Yoshitaka Itow, Rintaro Kirikawa, Naoki Koshimoto, Yutaka Matsubara, Sho Matsumoto, Shota Miyazaki, Yasushi Muraki, Greg Olmschenk, Clément Ranc, Arisa Okamura, Nicholas J. Rattenbury, Yuki Satoh, Takahiro Sumi, Daisuke Suzuki, Stela Ishitani Silva, Taiga Toda, Paul . J. Tristram, Aikaterini Vandorou, Hibiki Yama, Michael D. Albrow, Sun-Ju Chung, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, Yoon-Hyun Ryu, In-Gu Shin, Yossi Shvartzvald, Jennifer C. Yee, Sang-Mok Cha, Dong-Jin Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W. Pogge, Andrzej Udalski, Przemek Mróz, Rados law Poleski, Jan Skowron, Micha l K. Szymański, Igor Soszyński, Pawe l Pietrukowicz, Szymon Kozlowski, Krzysztof Ulaczyk, Krzysztof A. Rybicki, Patryk Iwanek, Marcin Wrona, Mariusz Gromadzki. 2022-05-16. MOA-2019-BLG-008Lb: a new microlensing detection of an object at the planet/brown dwarf boundary. https://doi.org/10.3847/1538-3881%2Fac78ed

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