Planets found by astrometry
6 of the confirmed exoplanets in this catalog, 0.1% of the total, were found by astrometry: tracking a star's side-to-side wobble against the background sky, the first of them in 2013.
Radial velocity measures the part of a star's wobble aimed at us; astrometry measures the part across our line of sight, by tracking the star's position against more distant background stars. It is the oldest idea in the subject and the hardest to execute: the wobble Jupiter induces in the Sun, seen from thirty light-years, is a few millionths of a degree.
Its advantage is that it gives a true mass rather than a minimum, because it reveals the full geometry of the orbit rather than one component of it. It is also most sensitive to massive planets on wide orbits, which is precisely where the other methods are weakest, so it fills in a part of the catalog nothing else reaches.
Precision. The measurement demands a stable instrument and years of observation, and it has only recently become productive. The handful of astrometric discoveries here reflect how young the technique's practical era is, not how useful it will be.
| # | World | Distance | Discovered |
|---|---|---|---|
| 1 | GJ 896 A b | 20.4 ly | 2022 |
| 2 | DENIS-P J082303.1-491201 b | 67.7 ly | 2013 |
| 3 | HIP 66074 b | 116 ly | 2023 |
| 4 | Gaia-5 b | 134 ly | 2025 |
| 5 | Gaia-4 b | 240 ly | 2025 |
| 6 | HD 128717 b | 240 ly | 2025 |
How does astrometry find planets?
6 of the confirmed exoplanets in this catalog, 0.1% of the total, were found by astrometry: tracking a star's side-to-side wobble against the background sky, the first of them in 2013.
What was the first planet found by astrometry?
DENIS-P J082303.1-491201 b, confirmed in 2013. The method has found 6 confirmed worlds since, the most recent of them in 2025.
What can this method not see?
Precision. The measurement demands a stable instrument and years of observation, and it has only recently become productive. The handful of astrometric discoveries here reflect how young the technique's practical era is, not how useful it will be.
How is astrometry different from radial velocity?
They measure perpendicular halves of the same wobble. Radial velocity sees the motion toward and away from us, through a shift in the star's light. Astrometry sees the motion side to side, as a change in the star's position on the sky, and that gives the orbit's true geometry.
Why are there so few astrometric discoveries?
Because the effect is tiny: microarcseconds, or millionths of a degree. It took decades of instrument development before the measurement became routine, and the technique's productive era is only beginning.
Keep exploring: every detection method · discoveries by year