Transit-based exoplanet survey finds its first microlensing exoplanet

Physics World reports that NASA's TESS mission has detected its first exoplanet using a technique called microlensing. The planet, a super-Jupiter about one point six three times the size of Jupiter, orbits an orange dwarf star at roughly the same distance that Jupiter orbits our Sun. Unlike the transit method TESS was designed for—which watches for stars dimming as planets pass in front of them—microlensing uses gravity to bend and magnify light from a distant background star, revealing hidden planets. Astronomers initially spotted the unexpected brightening with the retired Gaia space telescope, but only TESS's dense observations, taken every two hundred seconds over nearly sixty days, revealed the telltale signature of the planet itself. The discovery matters because microlensing excels at finding planets orbiting at Earth-like distances or farther out, places where transits are harder to spot. As one of the lead researchers notes, the downside is that microlensing events happen once and they're gone—an opportunity you don't get a second chance to observe.

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