Stellar Data for

Type of Star:

Spectral Class:




Surface Temperature:

Yellow Dwarf


46 Lightyears

1,82 L

1,03 Solar Masses

5800 K

The Planet of 47 Ursae Majoris


Orbital Radius:

Orbital Period:



2,45 Jupiter Masses

2,09 AU

3 Years



Comparison to Solar System


47 Ursae Majoris b

Speculations about 47 Ursae Majoris b

The giant planet 47 Ursae Majoris b with one of its small, dead worlds

47 Ursae Majoris b is a rather promising world, orbiting its parent star at a distance where liquid water may still exist. But 47 Ursae Majoris b is a cold world, though. Circling its sun at twice the distance than Earth, this planet would be as cold as Mars.

Being more than twice as massive than Jupiter, 47 Ursae Majoris b may have moons of almost Earth's size. As they formed at a larger distance from the parent star, these moons would have a larger percentage of water and volatile gases.


Not as dry as with 70 Virginis b and not as frozen as with Jupiter, the moons of 47 Ursae Majoris b would be something in between. The may have silicate cores and mantles, and their surface would be covered by considerable layers of ice. The closer such a moon is to the planet, the more it would be squeezed and heated by the planet's immense gravity. These worlds may be tectonically active. In areas of intense volcanic activity, liquid water may exist at the surface.

A small pond on a moon of 47 Ursae Majoris b, warmed by volcanic forces from the deep interior

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