Planetary Classification (WIP)

A planet is a celestial body in orbit around a star or stellar remnants, that has sufficient mass for
self-gravity and is nearly spherical in shape. A planet must not share its orbital region with other
bodies of significant size (except for its own satellites), and must be below the threshold for
thermonuclear fusion of deuterium.

If a celestial body meets those requirements, it is considered a planet; at that point, the planet is
further classified by its atmosphere and surface conditions into one of twenty-two categories.


Class A - Geothermal

AGE 0-2 billion years old
DIAMETER 1,000 - 10,000 km
LOCATION Hot Zone/Ecosphere/Cold Zone
SURFACE Partially molten, very hot
ATMOSPHERE Carbon dioxide, hydrogen
EVOLUTION Cools to become Class C
LIFE FORMS None
EXAMPLES Gothos

Class A planets are very small, barren
worlds rife with volcanic activity. This
activity traps carbon dioxide in the
atmosphere and keeps temperatures
on Class A planets very hot, no matter
the location in a star system. When
the volcanic activity ceases, the
planet "dies" and is then considered a
Class C planet.


Class B - Geomorteus

AGE 0-10 billion years old
DIAMETER 1,000 - 10,000 km
LOCATION Hot Zone
SURFACE Partially molten
ATMOSPHERE Extremely tenuous
EVOLUTION N/A
LIFE FORMS None
EXAMPLES Mercury, Nebhilum

Class B planets are generally small
worlds located within a star system's
Hot Zone. Highly unsuited for
humanoid life, Class B planets have
thin atmospheres composed primarily
of helium and sodium. The surface is
molten and highly unstable;
temperatures range from 450° in the
daylight, to nearly -200° at night. No
life forms have ever been observed on
Class B planetoids.


Class C - Geoinactive
AGE 2-10 billion years old
DIAMETER 1,000 - 10,000 km
LOCATION Hot Zone/Ecosphere/Cold Zone
SUFRACE Barren
ATMOSPHERE None
EVOLUTION N/A
LIFE FORMS None
EXAMPLES Psi 2000

When all volcanic activity on a Class A
planet ceases, it is considered Class C.
Essentially dead, these small worlds
have cold, barren surfaces and
possess no geological activity.


Class D - Dwarf

Also known as Plutonian objects,
these tiny worlds are composed
primarily of ice and are generally not
considered true planets. Many moons
and asteroids are considered Class D,
as are the larger objects in a star
system's Kuiper Belt. Most are not
suitable for humanoid life, though
many can be colonized via pressure
domes.


Class E - Geoplastic

Class E planets represent the earliest
stage in the evolution of a habitable
planet. The core and crust is
completely molten, making the planets
susceptible to solar winds and
radiation and subject to extremely
high surface temperatures. The
atmosphere is very thin, composed of
hydrogen and helium. As the surface
cools, the core and crust begin to
harden, and the planet evolves into a
Class F world.


Class F - Geometallic

A Class E planet makes the transition
to Class F once the crust and core
have begun to harden. Volcanic
activity is also commonplace on Class F
worlds; the steam expelled from
volcanic eruptions eventually
condenses into water, giving rise to
shallow seas in which simple bacteria
thrive. When the planet's core is
sufficiently cool, the volcanic activity
ceases and the planet is considered
Class G.


Class G - Geocrystalline

After the core of a Class F planet is
sufficiently cool, volcanic activity
lessens and the planet is considered
Class G. Oxygen and nitrogen are
present in some abundance in the
atmosphere, giving rise to increasingly
complex organisms such as primitive
vegetation like algae, and animals
similar to sponges and jellyfish. As the
surface cools, a Class G planet can
evolve into a Class H, K, L, M, N, O, or
P class world.


Class H - Desert

A planet is considered Class H if less
than 20% of its surface is water.
Though many Class H worlds are
covered in sand, it is not required to
be considered a desert; it must,
however, receive little in the way of
precipitation. Drought-resistant
plants and animals are common on
Class H worlds, and many are
inhabited by humanoid populations.
Most Class H worlds are hot and arid,
but conditions can vary greatly.


Class I - Ice Giant (Uranian)

Also known as Uranian planets, these
gaseous giants have vastly different
compositions from other giant worlds;
the core is mostly rock and ice
surrounded by a tenuous layers of
methane, water, and ammonia.
Additionally, the magnetic field is
sharply inclined to the axis of
rotation. Class I planets typically form
on the fringe of a star system.


Class J - Gas Giant (Jovian)

Class J planets are massive spheres of
liquid and gaseous hydrogen, with
small cores of metallic hydrogen.
Their atmospheres are extremely
turbulent, with wind speeds in the
most severe storms reaching 600 kph.
Many Class J planets also possess
impressive ring systems, composed
primarily of rock, dust, and ice. They
form in the Cold Zone of a star
system, though typically much closer
than Class I planets.


Class K - Adaptable

Though similar in appearance to Class
H worlds, Class K planets lack the
robust atmosphere of their desert
counterparts. Though rare, primitive
single-celled organisms have been
known to exist, though more complex
life never evolves. Humanoid
colonization is, however, possible
through the use of pressure domes
and in some cases, terraforming.


Class L - Marginal

Class L planets are typically rocky,
forested worlds devoid of animal life.
They are, however, well-suited for
humanoid colonization and are prime
candidates for terraforming. Water is
typically scarce, and if less than 20%
of the surface is covered in water,
the planet is considered Class H.