資料來源:
http://www.geocities.com/voyager_gi/planetclass.html
原文:
Class A (Gas Supergiant):
Class A planets are usually found in a star's outer or "cold zone". They
are ususally between 140,000 and 10 million kilometres in diameter and are
able to radiate heat due to high core temperatures. Their surface is comprised
of gaseous hydrogen and hydrogen compounds and is as a result of low stellar
radiation and high planet gravity. An example of a Class A planet is Jupiter.
Class B (Gas Giant):
Class B planets, like Class A planets, are also found in a star's
"cold zone". They are smaller than Class A planets and are usually between
50,000 and 140,000 kilometers in diameter. They have high core temperatures
but do not radiate as much heat as Class A planets. Their surface is also
composed from gaseous hydrogen and hydrogen compounds, due to the low stellar
radiation and high planet gravity. An example of a Class B planet is Saturn.
Class C (Reducing):
Class C planets can be found in a star's "habitable zone" and are usually
between 10,000 and 15,000 kilometers in diameter. They have dense atmospheres,
which leads to the "greenhouse effect". As a result, Class C planets have very
high surface temperatures and the only water found there is in vapour form.
An example of a Class C planet is Venus.
Class D (Geo-Plastic):
Class D planets are usually found in a star's "habitable zone" and are
usually between 10,000 and 15,000 kilometers in diameter. They have a molten
surface because they have been formed recently. Their atmosphere contains
many hydrogen compounds and reactive gases. A Class D planet will cool down
to form a Class E planet.
Class E (Geo-Metallic):
Class E planets are found in a star's "habitable zone" and have molten
cores. They are usually between 10,000 and 15,000 kilometers in diameter.
Their atmosphere still contains hydrogen compounds. A Class E planet will
cool down further to become a Class F planet.
Class F (Geo-Crystalline):
Class F planets are found in a star's "habitable zone" and are usually
between 10,000 and 15,000 kilometers in diameter. Their surfaces are still
crystallizing and their atmospheres still contain some toxic gases. A Class
F planet will cool down even further and will eventually become a Class C,
M or N planet.
Claflyinet):
Class G planets can be found in any of a star's zones and are usually
between 8,000 and 15,000 kilometers in diameter. Their surfaces are usually
hot and their atmospheres contain heavy gases and metal vapours.
Class H (Geo-Thermal):
Class H planets are found in a star's "habitable zone" or "cold one" and
are usually between 1,000 and 10,000 kilometers in diameter. Their surfaces
are partially molten and their atmospheres contain many hydrogen compounds.
Class H planets coold own to form Class L planets.
Class I (Asteroid/ Moon):
A Class I planetary body can be found in any of a star's zones and is
usually found found in orbit of larger planets or in asteroid fields. They
are usually between 100 and 1,000 kilometers in diameter. They have no
atmosphere and their surfaces are barren and cratered. An example of a
Class I body is the Earth's moon.
Class J (Geo-Morteus):
Class J planets are usually found in a star's "hot zone" and are between
1,000 and 10,000 kilometers in diameter. Their proximity to the star means
that they have very high surface temperatures and their atmospheres are
extremely tenuous with few chemically active gases. An example of a Class
J planet is Mercury.
Class K (Adaptable):
Class K planets are found in a star's "habitable zone" and are adaptable
for humanoid colonization through the use of pressure doems and other
life-support devices. They are usually between 5,000 and 10,000 kilometers
in diameter. Their atmospheres are thin. Only small amounts of water can be
found on a Class K planet. An example of this type of planet is Mars.
Class L (Geo-Inactive):
Class L planets are found in a star's "habitable zone" or "cold zone" and
are usually between 1,000 and 10,000 kilometers in diameter. Their
atmospheres are frozen due to low solar radiation and minimal internal
heat. An example of a Class L planet is Pluto
Class M (Terrestrial):
Class M planets are found in a star's "habitable zone" and are usually
between 10,000 and 15,000 kilometers in diameter. Their atmospheres contain
oxygen and nitrogen. Water and life-forms are abundant. If over 97% of the
surface is covered by water, then the planet is designated a Class N planet.
Examples of Class M planets include Earth, Cardassia and Vulcan.
Class N (Pelagic):
Class N planets are usually found in a star's "habitable zone" and are
usually between 10,000 and 15,000 kilometers in diameter. Their atmospheres,
like those of Class M planets, are composed of nitrogen and oxygen and water
and life-forms are usually abundant. They are differentiated from Class M
planets by the fact that at least 97% of their surfaces are covered by water.
Class S (Near Star):
Class S planets are found in a star;'s "cold zone" and are between 50
million and 120 million kilometers in diameter. Their high core temperaures
cause them to radiate heat and light. These are the largest planets there
can be as Class S planets that reach this size usually become stars.
Class T (Gas Ultragiant):
Class T planets are found in a star's "cold zone" and are between 10
million and 50 million kilometers in diameter. Their high core temperatures
mean that enough heat is radiated to keep water in a liquid state despite
the low solar radiation the planet receives.
Class Y (Demon):
Class Y planets and planetoids can be found in any of a stars zones and
are usually between 10,000 and 15,000 kilometers in diameter. A Class Y
atmosphere has been deemed by Starfleet to be the most inhospitable
enviroment to humanoid life that there is. Its atmosphere it turbulent and
is saturated with poisonous chemicals and thermionis radiation. Its surface
temperature can reach in excess of 500K. Transport and communication are
difficult and sometimes near impossible. Even entering its enviroment is a
dangerous prospect.
