TESS Detection Reveals Microlensing Super‑Jupiter Gaia23bra b

Overview

• Researchers tracing a 2023 Gaia alert rechecked archived TESS frames and found the same microlensing event recorded at minute-level cadence, allowing a fuller light-curve analysis.
• The team’s analysis, published July 1 in The Astrophysical Journal Letters, identifies Gaia23bra b as a super-Jupiter about 1.6 times the mass of Jupiter orbiting an orange dwarf roughly 0.8 times the Sun’s mass at a distance near 40,000 light-years.
• Gravitational microlensing occurs when a foreground star magnifies a background star’s light and a planet around the foreground star produces short, telltale deviations in the brightening that reveal its mass ratio and orbit.
• Authors including Michael Fausnaugh and colleagues at the University of New Mexico show this is the first bound microlensing planet found using TESS archival data and demonstrate a practical new way to mine past TESS observations for similar events.
• The result complements transit surveys by probing cold, wide-orbit giants that transits miss and strengthens methods planned for future microlensing surveys such as NASA’s Roman Space Telescope.