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OGLE-2017-BLG-1038 : a possible Brown-dwarf binary revealed by spitzer microlensing parallax
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OGLE Collaboration (Including:
). (2022) OGLE-2017-BLG-1038 : a possible Brown-dwarf binary revealed by spitzer microlensing parallax. The Astronomical Journal, 164 (3). 102. doi:10.3847/1538-3881/ac7d4c ISSN 1538-3881.
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Official URL: https://doi.org/10.3847/1538-3881/ac7d4c
Abstract
We report the analysis of microlensing event OGLE-2017-BLG-1038, observed by the Optical Gravitational Lensing Experiment, Korean Microlensing Telescope Network, and Spitzer telescopes. The event is caused by a giant source star in the Galactic Bulge passing over a large resonant binary-lens caustic. The availability of space-based data allows the full set of physical parameters to be calculated. However, there exists an eightfold degeneracy in the parallax measurement. The four best solutions correspond to very-low-mass binaries near ( M1=170−50+40MJ and M2=110−30+20MJ ), or well below ( M1=22.5−0.4+0.7MJ and M2=13.3−0.3+0.4MJ ) the boundary between stars and brown dwarfs. A conventional analysis, with scaled uncertainties for Spitzer data, implies a very-low-mass brown-dwarf binary lens at a distance of 2 kpc. Compensating for systematic Spitzer errors using a Gaussian process model suggests that a higher mass M-dwarf binary at 6 kpc is equally likely. A Bayesian comparison based on a galactic model favors the larger-mass solutions. We demonstrate how this degeneracy can be resolved within the next 10 years through infrared adaptive-optics imaging with a 40 m class telescope.
Item Type: | Journal Article | ||||||
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Divisions: | Faculty of Science, Engineering and Medicine > Science > Physics | ||||||
SWORD Depositor: | Library Publications Router | ||||||
Journal or Publication Title: | The Astronomical Journal | ||||||
Publisher: | The American Astronomical Society | ||||||
ISSN: | 1538-3881 | ||||||
Official Date: | 18 August 2022 | ||||||
Dates: |
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Volume: | 164 | ||||||
Number: | 3 | ||||||
Article Number: | 102 | ||||||
DOI: | 10.3847/1538-3881/ac7d4c | ||||||
Status: | Peer Reviewed | ||||||
Publication Status: | Published | ||||||
Access rights to Published version: | Open Access (Creative Commons) | ||||||
Date of first compliant deposit: | 11 October 2022 | ||||||
Date of first compliant Open Access: | 11 October 2022 | ||||||
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