We report a planet in a binary that was discovered from the analysis of the microlensing event OGLE-2018-BLG-1700. We identify the triple nature of the lens from the fact that the anomaly pattern can be decomposed into two parts produced by two binary-lens events, in which one binary pair has a mass ratio of ∼0.01 between the lens components and the other pair has a mass ratio of ∼0.3. We find two sets of degenerate solutions, in which one solution has a projected separation between the primary and its stellar companion less than the angular Einstein radius θE (close solution), while the other solution has a separation greater than θE (wide solution). From the Bayesian analysis with the constraints of the event timescale and angular Einstein radius, we find that the planet has a mass of 4.4-2.0+3.0MJ and the stellar binary components have masses of 0.42-0.19+0.29M⊙ and 0.12-0.05+0.08M⊙, respectively, and the distance to the lens is DL=7.6-0.9+1.2kpc. The planet is a circumstellar planet according to the wide solution, while it is a circumbinary planet according to the close solution.
Bibliographical notePublisher Copyright:
© 2020. The American Astronomical Society. All rights reserved.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science