|Orbital period|| 356.7153 Terran days|
324.0820 Dionean days
|Orbital axis||113,219,335 km|
|Rotation period||26 h 25 min|
|Mean diameter||10198 km|
| 326,700,000 km²|
|Surface gravity||8.409 m/s²|
|Atmospheric pressure (at MSL)||879 mbar|
|Atmospheric Composition||63%N, 22%O, 9% He, 4% Ar, 1%CO2|
| 0 (as of March 2006)|
|Countries||none recognized (according to UN)|
Dione is a planet of Saturn. It's also the most inhabitable body in the Sol Barycentral B system.
Dione's extreme habitability consists of few things:
- Only 43% of the surface is covered by seas and oceans, but they are distributed evenly around the planet
- Most of the seas is near 50° in latitude
- Flat topography
- Earthlike temperatures
- Mean temperature only 11 Kelvin higher than on Earth
- Big axial tilt helps to get warmth near polar regions
It is estimated that with the current available technology, Dione could be home for 15 billion people.
Race to Dione
As of July 2006, there are two manned spacecraft going to Dione. With current estimates, the Japanese (5 people) will arrive to Dione on March 17, 2007. The Europeans (3 French, 4 Italians) will arrive on March 22, 2007. In July 25, 2006, the Japanese were 8.34 Tm and Europeans 8.24 Tm from Saturn, their mutual distance being 109 Gm.
A British-Irish group has announced its intention to leave Earth on August 1, 2006 and land on Dione in May 2008.
Dione has only little tectonic activity. The thermohaline circulation is relatively effective.
- Tallest mountain: 3,019 metres at 34°N, 145°W
- Deepest trench: 2,493 metres at 20°N, 90°W
- Warmest place: 39°C Winter, 52°C Summer (at 21°S, 56°E)
- Coldest place: -50°C Winter, 9°C Summer (at 84°S, 45°E)
- Greatest avg. rainfall: 8645 mm/year (at 45°N, 174°E)
- Lowest avg. rainfall: 2 mm/year (at 28°S, 61°E)
- Polar, 2.7 Mm²
- Glaciers, 0.8 Mm²
- Tundra, 1.9 Mm²
- Temperate, 25.0 Mm²
- Boreal, 2.1 Mm²
- Mixed forest, 1.9 Mm²
- Broadleaf, 10.3 Mm²
- Steppe, 8.8 Mm²
- Desert, 1.9 Mm²
- Subtropical, 35.4 Mm²
- Jungle, 14.3 Mm²
- Monsoon, 14.9 Mm²
- Desert, 6.2 Mm²
- Tropical, 121.8 Mm²
- Jungle, 76.2 Mm²
- Savannah, 45.6 Mm²
- Huyver, 119,000,000
- Huygentia, 62,300,000
- North Verrieria, 17,500,000
- South Verrieria, 39,200,000
- West Dione, 43,500,000
- Saturnia, 24,900,000
- Heliania, 18,600,000
- Muyahia, 8,800,000
- Islands, 11,600,000
- Greater New Caribia, 900,000
- Oeljaland, 700,000
Dione has two natural satellites.
- Mass: 39/1000000 Diones
- Diameter: 443 km
- Semi-major axis: 58910 km
- Revolution period: 2.9916 Terran days
- Synodic period: ?
- Mass: 2.6 /1000000 Diones
- Diameter: 180 km
- Semi-major axis: 109230 km
- Revolution period: 7.5532 Terran days
- Synodic period: ?
View from Earth
The position angle as measured from Saturn is the key to visibility for two reasons:
- the primary source of light in Dione is Saturn; to see Dione, one has to see the side of it illuminated by Saturn;
- when approaching the same line of sight with Saturn, visibility of Dione is inhibited by the greater glare of Saturn.
The greatest angular separation between Saturn and Dione is 0.0057 rad (0.33 degrees).
While Saturn passes in front of Dione, a maximum apparent magnitude of 2.8 is reached. However, angular proximity to Saturn makes observation by the simplest methods impossible: normally Dione is seen best with a magnitude ~3.5, while being further.