NASA (Exoplanet Catalog artwork)8 Ursae Minoris b
also named HallaThe planet that should have been swallowed by its star
Overview
8 Ursae Minoris b is a gas giant exoplanet that orbits a K-type star. Its mass is 1.65 Jupiters, it takes 93.3 days to complete one orbit of its star, and is 0.462 AU from its star. Its discovery was announced in 2015.
Source: NASA Exoplanet Catalog
Why it matters
- Orbits a red-giant star at half an Earth–Sun distance — inside the radius the star reached while swelling.
- A 2023 study proposed the star skipped its expansion after merging with a companion, sparing the planet.
- Alternatively it formed late from merger debris, making it a 'second-generation' planet.
NASA puts it this way: “8 Ursae Minoris b is a gas giant exoplanet that orbits a K-type star. Its mass is 1.31 Jupiters, it takes 93.4 days to complete one orbit of its star, and is 0.49 AU from its star. Its discovery was announced in 2015.”
Discovery & system
- Discovered
- 2015 · Radial Velocity · Bohyunsan Optical Astronomical Observatory
- Discovery paper
- Lee et al. 2015
- Host star
- 8 UMi · K0 · 4,847 K · 1.51 M☉
- System
- 1 known planet
The system
| World | Period | Distance | Radius | Mass | Temp. |
|---|---|---|---|---|---|
| 8 UMi b | 93.3 d | 0.462 AU | 1.2 R♃ | ≥ 1.65 M♃ | 1,126 K |
this worldhabitable zone 6.91 AU – 12.15 AUlog distance scaleorbital phases are arbitrarystar: K0, 4,847 K
By the numbers
- Radius
- 1.2 R♃13.5 R⊕
- Mass
- ≥ 1.65 M♃524 M⊕ · minimum mass (M sin i)
- Orbital period
- 93.3 d0.26 yr
- Distance from star
- 0.462 AU69 million km
- Eccentricity
- 0.062elliptical
- Equilibrium temp.
- 1,126 K853 °C
- Starlight received
- 248 × Earth
- Distance from Earth
- 530 ly162.6 pc
- Density
- 1.17 g/cm³0.21 × Earth
Sources
Image: NASA (Exoplanet Catalog artwork) · NASA media: generally free of copyright · image page
Text: NASA Exoplanet Catalog. Taglines and highlights are editorial.