NASA (Exoplanet Catalog artwork)Gamma Cephei Ab
also named TadmorArguably the first exoplanet detected — in 1988, then retracted, then confirmed
Overview
Gamma Cephei Ab, formally named Tadmor, is an exoplanet approximately 45 light-years away in the constellation of Cepheus that orbits Gamma Cephei A. The planet was suspected to exist in 1988, and later confirmed in 2003, technically making it the first exoplanet discovered.
Source: Wikipedia
NASA: Gamma Cephei b is a gas giant exoplanet that orbits a K-type star. Its mass is 9.4 Jupiters, it takes 2.5 years to complete one orbit of its star, and is 1.978 AU from its star. Its discovery was announced in 2003.
Why it matters
- Canadian astronomers reported a signal in 1988 but withdrew it in 1992 as the data were not conclusive.
- Confirmed in 2003 as a planet of about 1.8 Jupiter masses in a 2.5-year orbit.
- Orbits a star in a close binary, where planet formation was thought to be difficult.
NASA puts it this way: “Gamma Cephei b is a gas giant exoplanet that orbits a K-type star. Its mass is 9.4 Jupiters, it takes 2.5 years to complete one orbit of its star, and is 2.05 AU from its star. Its discovery was announced in 2003.”
Discovery & system
- Discovered
- 2003 · Radial Velocity · Multiple Observatories
- Discovery paper
- Hatzes et al. 2003
- Host star
- gam Cep · K1 III-IV · 4,775 K · 1.26 M☉
- System
- 1 known planet, 2 stars
The system
| World | Period | Distance | Radius | Mass | Temp. |
|---|---|---|---|---|---|
| gam Cep b | 904 d | 1.98 AU | 1.12 R♃ | 9.4 M♃ | 356 K |
By the numbers
- Radius
- 1.12 R♃12.5 R⊕
- Mass
- 9.4 M♃2,988 M⊕
- Orbital period
- 904 d2.48 yr
- Distance from star
- 1.98 AU296 million km
- Eccentricity
- 0.07elliptical
- Equilibrium temp.
- 356 K83 °C
- Starlight received
- 3 × Earth
- Distance from Earth
- 46 ly14.1 pc
- Density
- 8.41 g/cm³1.53 × Earth
Sources
Image: NASA (Exoplanet Catalog artwork) · NASA media: generally free of copyright · image page
Text: Wikipedia (CC BY-SA 4.0). Taglines and highlights are editorial.