Radial velocity follow-up disproves Gaia exoplanet candidate around HD 12800

Star system: 54 Cassiopeiae | Distance from the Sun: 88.1 light years

The Gaia mission’s precise astrometric data has enabled the discovery of new exoplanet candidates, but confirming these planets can be challenging. In 2022, Gaia Data Release 3 (DR3) announced a candidate planet around the bright, Sun-like star HD 12800. However, follow-up observations using the TRES spectrograph failed to detect any evidence of the proposed planet. The data show that if the planet had existed as originally reported, it would have been easily detected by the radial velocity measurements.

This result led to the retraction of the Gaia exoplanet candidate around HD 12800. The study highlights the importance of intermediate-precision radial velocity spectrographs in confirming or refuting Gaia astrometric planet discoveries, especially for stars where high-precision instruments are not available. As Gaia continues to release new data, such follow-up observations will be crucial for validating exoplanet candidates and ensuring the reliability of astrometric planet discoveries.

Key findings
- Radial velocity observations failed to confirm the Gaia DR3 exoplanet candidate around HD 12800
- The originally proposed planet would have been easily detected if it existed
- The Gaia candidate was retracted after follow-up
- Intermediate-precision radial velocity spectrographs are valuable for confirming Gaia exoplanet candidates
- Such follow-up will be important for future Gaia data releases

Scientific study

A Planetary Illusion's Funeral: Non-detection of a Gaia DR3 Exoplanet Candidate, and the Role of Intermediate-precision Radial Velocities in Gaia Exoplanet Follow-up (external link)