New Planet Classification

## Origin

With Space Engine 0.990 being released, the developers revamped the planet classification to be more broad, simple, and universal. Including the temperature, mass, humidity, and atmospheric and hydrosphere properties. This classification went through many revamps, though has stayed the same for the past few years. The Space Engine blog-post which contains this classification can be found here.

(The old classification has also been included here for convenience)

## New Planet Classification

### Temperature

* **Frigid** - 0K+ (Frozen in 0.9.8.0 and below)
* **Cold** - 90K+
* **Cool** - 170K+
* **Temperate** - 250K+
* **Warm** - 330K+
* **Hot** - 500K+
* **Torrid** - 1000K+ (Scorched in 0.9.8.0 and below)

### Volatiles

* **Airless** - A planet with an atmospheric pressure less than 1 nanobar;
* **Arid** - A planet with atmospheric pressure greater than 1 nanobar, but with no liquids on its surface;
* **Lacustrine** - A planet with a small amount of liquid on its surface (lakes and rivers), and, obviously, with an atmosphere (because liquid cannot exist in a vacuum);
* **Marine** - A planet with seas of a liquid substance, i.e. a significant amount of it, but not completely covering the surface;
* **Oceanic** - A planet with a global ocean, completely covering the surface;
* **Superoceanic** - A planet with a very deep ocean (hundreds of kilometers deep), with exotic forms of ice forming on its bottom (ice VI and ice VII).

### Mass

#### Solid Planets (Ferria, Carbonia, Terra, Aquaria)

* **Micro** - 0+ M⊕
* **Mini** - 0.002 M⊕
* **Sub** - 0.02 M⊕
* **No Prefix** - 0.2 M⊕
* **Super** - 2 M⊕
* **Mega** - 10 M⊕

#### Ice Giants (Neptunes)

* **Mini** - 0+ M⊕
* **Sub** - 4 M⊕
* **No Prefix** - 10 M⊕
* **Super** - 25 M⊕
* **Mega** - 62.5 M⊕

#### Gas Giants (Jupiters)

* **Sub** - 0+ M♃
* **No Prefix** - 0.2 M♃
* **Super** - 2 M♃
* **Mega** - 10 M♃

### Bulk Composition

* **Ferria** - Metals (iron, nickel) and siderophilic elements such as sulfur. The boundary is > 50% by mass.
* **Carbonia** - Carbon and its compounds like carbides, also CO and methane. The boundary is > 25% by mass.
* **Aquaria** - Water in the form of exotic ices and liquid (but not vapor or supercritical fluid - that is a minineptune). The boundary is > 25% by mass.
* **Terra** - Not ferria, not carbonia, and not aquaria. Rocky planet whose primary component is silicates (rocks).
* **Jupiter** - Hydrogen and Helium. The boundary is > 25% by mass.
* **Neptune** - Not any of the previous classes. Typically, H/He is less than 25%; other substances are water/ammonia/methane and a rocky core. An aquaria with a supercritical vapor atmosphere is classified as a minineptune/subneptune.

### Old Planet classes

Here's a list of planetary classes for version 0.9.8.0 and lower:

* **Selena** - Rocky planets without an atmosphere. Mercury and the Moon are examples.
* **Ice World** - A planet whose surface is covered primarily by solidified volatiles.
* **Titan** -Planets similar to the moon Titan mainly composed of rocky material, water ice and organic compounds.
* **Desert** - A planet with atmospheric pressure greater than 1 nanobar, but with no liquids on its surface.
* **Terra** - Rocky planet whose primary component is silicates (rocks).
* **Oceania** - A planet with a global ocean, completely covering the surface.
* **Ice Giant** - Gaseous planets composed of heavier elements like carbon, sulfur, oxygen and nitrogen. Uranus and Neptune are examples.
* **Gas Giant** - Surfaceless planets composed of gases such as Hydrogen and Helium. Jupiter and Saturn are examples.

### "With life"

Does not fall into any of the previous classification categories. Defines that life is present on a planet.

## See Also

Space Engine Wiki's planet page

Original planet classification before revamp

## References

1. ↑ https://spaceengine.org/news/blog170924/