Alpha Centauri Ab
The candidate planet imaged by JWST (third picture, circled with the label "S1") | |
| Discovery | |
|---|---|
| Discovered by | K. Wagner, et al. |
| Discovery date | May–June 2019 (first imaging) February 2021 (reported) |
| Direct imaging | |
| Designations | |
| Alpha Centauri Ab, Rigil Kentaurus b, S1+C1 | |
| Orbital characteristics | |
| 1.64–2.23 AU | |
| Eccentricity | ~0.4 |
| 2 to 3 years | |
| Inclination | ~15 – 165° |
| Star | Alpha Centauri A (Rigil Kentaurus) |
| Physical characteristics | |
| 1.0–1.1 RJ | |
| Mass | 90–150 M🜨 |
| Temperature | 225 K |
Alpha Centauri Ab (also known as Rigil Kentaurus b, or originally as Candidate 1) is a candidate exoplanet that was first directly imaged around Alpha Centauri A in 2019 and reported in February 2021. If confirmed as an exoplanet, it would be the nearest, coldest, shortest-period and oldest directly imaged planet around a solar-type star, and Alpha Centauri would be the brightest planet-hosting star (see list of brightest stars). The planet is expected to be a gas giant based on physical properties. Additional observations are needed to confirm its existence.