Space

NASA's TESS Finds Distant Planet Via Microlensing

Is microlensing the next frontier in planet hunting or the key to finding habitable Earth-like worlds?

Published JUL 2

NASA's TESS Finds Distant Planet Via Microlensing

Story

Above: Artist's concept visualizing Gaia23bra b, the first microlensing planet orbiting a distant star found by NASA’s TESS. Image credit: NASA’s Goddard Space Flight Center

The Facts

NASA's TESS mission has identified a planet orbiting a distant star via gravitational microlensing for the first time, a method that was not anticipated when the satellite launched. The planet, Gaia23bra b, is a super-Jupiter located nearly 40,000 light-years from Earth.
NASA Science
PHYS
Gaia23bra b was first flagged in 2023 by European Space Agency's now-retired Gaia space telescope, which detected a star brightening consistent with a microlensing event. Researchers later found that TESS had simultaneously captured the same event in its archived data.
NASA Science
Texas Tech University
The findings, published Wednesday in The Astrophysical Journal Letters, show Gaia23bra b is about 1.63 times Jupiter's mass and orbits an orange dwarf star roughly 80% of the sun's mass at a distance comparable to Jupiter's orbit.
Iopscience
PHYS
Of more than 6,000 known exoplanets, about three-quarters were found via the transit method, while microlensing has accounted for less than 5%. Microlensing is most sensitive to planets at Earth-like orbital distances or farther from their host stars.
NASA Science
Texas Tech University
The discovery suggests additional microlensing planets may be hidden within eight years of archived TESS data. Texas Tech University physicist Michael Fausnaugh, a co-author of the study, described the find as "a bit like a preview" of the microlensing work planned for NASA's Nancy Grace Roman Space Telescope.
PHYS
Texas Tech University
The Nancy Grace Roman Space Telescope, on track for launch in fall 2026, is expected to detect an estimated 1,000 microlensing planets and around 100,000 transiting planets by surveying the Galactic Bulge. Gaia23bra b is described as an important case study for Roman's planned microlensing survey.
NASA Science
Iopscience

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The Spin

Narrative A

TESS just proved it's far more capable than anyone imagined — spotting a super-Jupiter 40,000 light-years away via microlensing, a method it was never designed for. This discovery means there are likely more microlensing planets buried in TESS' existing data, waiting to be found. Microlensing is the key to finding solar system-like planets that transit detection simply can't reach.

NASA Universe on X

PHYS

Narrative B

The real prize isn't just this one discovery — pairing TESS's microlensing finds in the galactic disk with Roman's upcoming survey of the galaxy's center will reveal how planets form across wildly different environments. The radiation-blasted galactic core may be hostile to life, making TESS' quieter survey region critical for understanding habitability. Roman and TESS together will transform the search for Earth-like worlds.