GRAVITATIONAL LENSING

Seeing microlensing from multiple angles

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Science  01 Dec 2017:
Vol. 358, Issue 6367, pp. 1144-1145
DOI: 10.1126/science.358.6367.1144-e

The Spitzer Space Telescope helped characterize gravitational microlensing of a brown dwarf star.

ILLUSTRATION; NASA/JPL-CALTECH/R. HURT (SSC)

General relativity shows that massive objects deflect light. If a background star and a moving foreground object line up with Earth, the system acts as a lens that appears to temporarily increase the brightness of the star, an effect known as gravitational microlensing. Zhu et al. observed a microlensing event simultaneously with the Kepler and Spitzer space telescopes, as well as from Earth. Because the two spacecraft and Earth have widely separated orbits, the same event was effectively viewed from three different angles. This allowed the determination of key physical parameters that would otherwise have multiple solutions, which showed that this event was caused by a brown dwarf in the bulge of our Milky Way Galaxy.

Astrophys. J. 849, L31 (2017).

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