Spitzer Microlensing of MOA-2016-BLG-231L: A Counter-rotating Brown Dwarf Binary in the Galactic Disk

Chung, Sun-Ju; Gould, Andrew; Skowron, Jan; Bond, Ian A.; Zhu, Wei; Albrow, Michael D.; Jung, Youn Kil; Han, Cheongho; Hwang, Kyu-Ha; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Kim, Yun-Hak; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; The KMTNet collaboration; Udalski, Andrzej; Poleski, Radek; Mróz, Przemek; Pietrukowicz, Paweł; Szymański, Michał K.; Soszyński, Igor; Kozłowski, Szymon; Ulaczyk, Krzysztof; Pawlak, Michał; The OGLE collaboration; Beichman, Charles A.; Bryden, Geoffery; Calchi Novati, Sebastiano; Carey, Sean; Gaudi, B. Scott; Henderson, Calen B.; The Spitzer team; Abe, Fumio; Barry, Richard; Bennett, David P.; Bhattacharya, Aparna; Donachie, Martin; Fukui, Akihiko; Hirao, Yuki; Itow, Yoshitaka; Kawasaki, Kohei; Kondo, Iona; Koshimoto, Naoki; Li, Man Cheung Alex; Matsubara, Yutaka; Muraki, Yasushi; Miyazaki, Shota; Nagakane, Masayuki; Ranc, Clément; Rattenbury, Nicholas J.; Suematsu, Haruno; Sullivan, Denis J.; Sumi, Takahiro; Suzuki, Daisuke; Tristram, Paul J.; Yonehara, Atsunori; MOA colllaboration, The
Referencia bibliográfica

The Astrophysical Journal, Volume 871, Issue 2, article id. 179, 13 pp. (2019).

Fecha de publicación:
2
2019
Número de autores
67
Número de autores del IAC
1
Número de citas
10
Número de citas referidas
9
Descripción
We analyze the binary microlensing event MOA-2016-BLG-231, which was observed from the ground and from Spitzer. The lens is composed of very-low-mass brown dwarfs (BDs) with {M}1={21}-5+12 {M}J and {M}2={9}-2+5 {M}J, and it is located in the Galactic disk {D}{{L}}={2.85}-0.50+0.88 {kpc}. This is the fifth binary brown dwarf discovered by microlensing, and the BD binary is moving counter to the orbital motion of disk stars. Constraints on the lens physical properties come from late-time, non-caustic-crossing features of the Spitzer light curve. Thus, MOA-2016-BLG-231 shows how Spitzer plays a crucial role in resolving the nature of BDs in binary BD events with short timescales (≲10 days).