John Carlos BaezHoly crap! The Gaia space telescope is expected to find 120,000 ± 22,000 planets orbiting other stars! Most will be super-Jupiters, because those are the easiest to find. But we'll know much more about other worlds than we do now.
The mission ran from 2014 to March 2025, orbiting at the Earth-Moon Lagrange point L2. It collected huge amounts of data. They repeatedly measured the positions of over a billion stars - so accurately that they could see a star moving by an amount equal to the size of a pinhead on the Moon, as seen from Earth!
They won't be able to process and release all this data until 2030. But some is already out, and they predict 7,500 ± 2,100 planet discoveries from this first release.
They've also found lots of other great stuff. Like 20 stars moving faster than the Galactic escape velocity: 7 leaving the Milky Way, and 13 approaching the Milky Way, which may have come from other galaxies. Like 4 stars orbiting each other. And like the Gaia-Enceladus population, the remains of a dwarf galaxy that collided with the Milky Way 10 billion years ago.
Despite our many other problems, we're in the golden age of astronomy.
On the Exoplanet Yield of Gaia Astrometry
We re-examine the expected yield of Gaia astrometric planet detections using updated models for giant-planet occurrence, the local stellar population, and Gaia's demonstrated astrometric precision. Our analysis combines a semi-analytic model that clarifies key scaling relations with more realistic Monte Carlo simulations. We predict $7{,}500 \pm 2{,}100$ planet discoveries in the 5-year dataset (DR4) and $120{,}000 \pm 22{,}000$ over the full 10-year mission (DR5), with the dominant error arising from uncertainties in giant-planet occurrence. We evaluate the sensitivity of these forecasts to the detection threshold and the desired precision for measurements of planet masses and orbital parameters. Roughly $1{,}900 \pm 540$ planets in DR4 and $38{,}000 \pm 7{,}300$ planets in DR5 should have masses and orbital periods determined to better than $20$%. Most detections will be super-Jupiters ($3$ - $13 M_{\rm J}$) on $2$ - $5$AU orbits around GKM-type stars ($0.4$ - $1.3 M_\odot$) within $500$ pc. Unresolved binary stars will lead to spurious planet detections, but we estimate that genuine planets will outnumber them by a factor of $5$ or more. An exception is planets around M-dwarfs with $a < 1$AU, for which the false-positive rate is expected to be about $50$%. To support community preparation for upcoming data releases, we provide mock catalogs of Gaia exoplanets and planet-impostor binaries.
Jeff Jarvis
Aure Free Press 