From phys.org: “Binary star composed of two brown dwarfs discovered by microlensing”

physdotorg
phys.org

May 23, 2017
Tomasz Nowakowski

1
Light curve of the microlensing event OGLE-2016-BLG-1469. The upper panel shows the enlarged view of the anomaly around the peak. The two lower panels show the residual from the binary-lens models with (orbit+parallax) and without (standard) considering higher-order effects. Credit: Han et al., 2017.

Using gravitational microlensing, astronomers have recently found a binary star composed of two brown dwarfs.

Now, a team of astronomers led by Cheongho Han of the Chungbuk National University in Cheongju, South Korea, reports the detection of a new brown-dwarf binary system from the analysis of the microlensing event OGLE-2016-BLG-1469. The discovery is the result of a joint effort of over 50 scientists working in three microlensing research groups. The team consists of researchers from the Korea Microlensing Telescope Network (KMTNet), the Optical Gravitational Lensing Experiment (OGLE) and the Microlensing Observations in Astrophysics (MOA).

For their observations of OGLE-2016-BLG-1469, MOA researchers employed the 1.8m telescope at the Mt. John University Observatory in New Zealand, while OGLE scientists used the 1.3m telescope located at the Las Campanas Observatory in Chile. When it comes to KMTNet, the astronomers utilized three identical 1.6m telescopes located at the Cerro Tololo Inter-American Observatory in Chile, the South African Astronomical Observatory in South Africa, and the Siding Spring Observatory in Australia.

Mt John University Observatory 1.8m MOA telescope NZ

1.3 meter OGLE Warsaw Telescope at the Las Campanas Observatory in Chile

SAAO 1.9 meter Telescope, at the SAAO observation station 15Kms from the small Karoo town of Sutherland in the Northern Cape, a 4-hour drive from Cape Town.

Gravitational microlensing, S. Liebes, Physical Review B, 133 (1964): 835

AAO 1.2m UK Schmidt Telescope at Siding Spring Observatory, near Coonabarabran, New South Wales, Australia

The newly discovered system is the third brown-dwarf binary detected with this technique. The finding was presented in a paper published May 16 on the arXiv pre-print server.

See the full article here .

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