Type of Star:

Spectral Class:

Distance:

Luminosity:

Mass:

Surface Temperature:

Remarkable Property:

Yellow Dwarf

G3V

56 Lightyears

1,33 L

1,0 Solar Masses

5700 K

This star is member of a binary system. 16 Cygni A and B orbit each other at a distance of 700 AU, once every 100.000 years.

Mass:

Orbital Radius:

Closest Distance to Star:

Widest Distance to Star:

Orbital Period:

Temperature:

Eccentricity:

1,67 Jupiter Masses

1,72 AU

0,6 AU

2,7 AU

2,2 Years

-90°C to +120°C

0,69

For many reasons 16 Cygni B b would fit well into the theories of planet formation. It is of roughly Jupiter's mass and orbits a sunlike star at a more acceptable average distance than 51 Pegasi b or others. There is only one flaw in 16 Cygni B b, and this is its highly eccentric orbit. During its summer, 16 Cygni B b is closer to the parent star than Venus is to our sun, while in winter it is much farther outside than even Mars. Such an orbit is more typical for a star than for a planet, or so it seemed before.

This bizarre world must have extreme variations in temperature - in summer it receives 22 times as much light and warmth as in winter. No one really knows how a gas giant would react to this. For Jupiter and Saturn, the higher, cooler clouds are also darker in color, and Saturn looks smoother than Jupiter, due to more haze in the upper atmosphere. Close to the star, 16 Cygni B b would be light and warm, with plenty of white clouds. Moving farther outside, the planet would darken and become hazier.

Springtime on a moon of 16 Cygni B b

No one knows how a planet could form at such an eccentric orbit. Current theories of planet formation predict a near circular orbit for planets, while stars usually form at highly eccentric orbits. The gravitational influence of 16 Cygni B's binary partner, 16 Cygni A, may have forced the young planet into its strange orbit.

Possible moons of 16 Cygni B b would suffer most from this orbit. An Earth-sized moon endowed with water and volatile gases may be completely frozen in winter, gradually thaw in spring, only to see its oceans boil in summer. Higher forms of life would be impossible, but organisms combining the skills of heat-loving Pyrodictium with those of the snow-algae may thrive there.

MAZEH T., KRYMOLOWSKI Y. & ROSENFELD G., 1996: The high eccentricity of the planet around 16 Cyg B. ApJ. Letters 477, L103

WILLIAMS D., KASTING J. & WADE R., 1997: Habitable moons around extrasolar giant planets. Nature, 385, 234