Steller and Planetary Classes

This is a refrence to my Solar Systems that I list.

Star Classes

Star Class O

The O & B class of Stars are the largest and brightest stars but also have a short stellar
life time, making them unsatiable for long term life. Class O stars are very hot and very
luminous, being bluish in colour; in fact, most of their output is in the ultraviolet range. These
are the rarest of all main sequence stars, constituting as few as 1 in 32,000. O-stars shine with a
power over a million times our Sun's output. Because they are so huge, Class O stars burn
through their hydrogen fuel very quickly, and are the first stars to leave the main sequence.

Star Class B

Class B stars are extremely luminous and blue. Their spectra have neutral helium and
moderate hydrogen lines. As O and B stars are so powerful, they live for a very short time. They
do not stray far from the area in which they were formed as they don't have the time. They
therefore tend to cluster together in what we call OB1 associations, which are associated with
giant molecular clouds. The Orion OB1 association is an entire spiral arm of our Galaxy (brighter
stars make the spiral arms look brighter, there aren't more stars there) and contains all of the
constellation of Orion. They constitute about 0.13% of main sequence stars -- rare, but much
more common than those of class O.

Star Class A

Class A stars are amongst the more common naked eye stars. As with all class A stars,
they are white or bluish-white. They have strong hydrogen lines and also ionized metals. They
comprise perhaps 0.63% of all main sequence stars. The Star Class A is the first star class that is
a feasible star with a habitable planet in orbit around the Star.

Star Class F

Class F stars are still quite powerful but they tend to be main sequence stars. Their spectra
is characterized by the weaker hydrogen lines and ionized metals, their colour is white with a
slight tinge of yellow. These represent 3.1% of all main sequence stars.

Star Class G

Class G stars are probably the best known, if only for the reason that our Sun is of this
class. They have even weaker hydrogen lines than F, but along with the ionized metals, they have
neutral metals. G is host to the "Yellow Evolutionary Void". Supergiant stars often swing
between O or B (blue) and K or M (red). While they do this, they do not stay for long in the G
classification as this is an extremely unstable place for a supergiant to be. These are about 8% of
all main sequence stars.

Star Class K

Class K are orangish stars which are slightly cooler than our Sun. Some K stars are giants
and supergiants, such as Arcturus while others like Alpha Centauri B are main sequence stars.
They have extremely weak hydrogen lines, if they are present at all, and mostly neutral metals.
These make up some 13% of main sequence stars.

Star Class M
Class M is by far the most common class if we go by the number of stars. All the red
dwarfs go in here and they are plentiful; over 78% of stars are red dwarfs, such as Proxima
Centauri. M is also host to most giants and some supergiants such as Antares and Betelgeuse, as
well as Mira variables. The spectrum of an M star shows lines belonging to molecules and
neutral metals but hydrogen is usually absent. Titanium oxide can be strong in M stars. The red
color is deceptive; it is because of the dimness of the star. When an equally hot object, a halogen
lamp (3000 K) which is white hot is put at a few kilometers distance, it appears like a red star.

Class Temperature Star color Mass Radius Luminosity
O 30,000 - 60,000 K Bluish ("blue") 60 15 1,400,000
B 10,000 - 30,000 K Bluish-white ("blue-white") 18 7 20,000
A 7,500 - 10,000 K White with bluish tinge ("white") 3.2 2.5 80
F 6,000 - 7,500 K White ("yellow-white") 1.7 1.3 6
G 5,000 - 6,000 K Light yellow ("yellow") 1.1 1.1 1.2
K 3,500 - 5,000 K Light orange ("orange") 0.8 0.9 0.4
M 2,000 - 3,500 K Reddish orange ("red") 0.3 0.4 0.04

Planetary Classes

My detailed planetary classification system was inspired from a lack of any classification
of planets like there is for stars. Like a star class there are different levels for each class (not listed
here) for example the Sun or Sol is a G2 star, the Earth would be a Class T3 Planet. A level 3 in a
planet class is the closest to the original planet that inspired the class. A planet’s Surface
Temperature & Astronomical units doesn’t matter in its levels only in its class and Astronomical
units do not necessarily change a planets class.
There are five levels, level 1 is a planet that varies from the original in one of several
ways for example a T1 class Planet would be an earth like world but it would different in these
areas its gravity, diameter, mass, or volume is between 50-75% lesser then a T3 planet. Level 2 is
a planet that varies from the original in one of several ways for example a T2 class Planet would
be an earth like world but it would different in these areas its gravity, diameter, mass, or volume
is between 25-49% lesser then a T3 planet. Level 3 is a planet that is the closest to the original
planet that inspired that class. Level 4 is a planet that varies from the original in one of several
ways for example a T4 class Planet would be an earth like world but it would different in these
areas its gravity, diameter, mass, or volume is between 25-100% greater. Level 5 is a planet that
varies from the original in one of several ways for example a T4 class Planet would be an earth
like world but it would different in these areas its gravity, diameter, mass, or volume is between
125% or greater then a T3 planet. For moons the term planet is replaced with moon.


Class A

Class B


Class C

The C class of planets are the hypothetical Chthonian planet type, is a hypothetical class
of celestial objects resulting from the stripping away of a gas giant's hydrogen and helium
atmosphere. Such atmospheric stripping is a likely result of close proximity to a star. The
remaining rocky or metallic core would resemble a terrestrial planet in many respects. Some
scientists suggest that Mercury is a Chthonian planet due to its high density and metal-rich core,
but other than this possibility no known Chthonian planets have been discovered.

Class D

The D class of planets are what are also classed Devil Planets, these D class of planets
have a Sulfuric atmosphere are typical hot planets, D class planets also have a volcanically active
geology. D Class planets also tend have liquid mercury rivers and/or molten Sulfur rivers, lakes,
& seas. There is no known planet that would fit into this class it is just another hypothetical
planet class.

Class E

The E class of planets are planets similar to Mercury, an E Class planet usually will have
no atmosphere or a very small and negligible atmosphere & has a geologic similarity to Mercury.

Class F



Class G

The G Class of planets is a class for gas giants that do not fit into the other classes for gas
giants. This is another hypothetical planet class for any gas giants that would not fit into the J, N,
S or U Classes.

Class I

An I class planet is a planet similar to Pluto, The I stands for Ice most I class planets are
ether in a far orbit from there star or orbit a Gas Giant Planet


Class J Planet

A J class planet is a planet that is similar to Jupiter, J class planets are similar to Jupiter
they are Gas Giants, they are usually larger than any other gas giants in a solar system, they also
don’t ordinarily have a ring system although it is possible.

Class L

The L class planet is a planet similar to the moon or Luna, low gravity, low or no
geologic activity, no atmosphere or a negligible atmosphere.

Class N

A N Class planet is a planet similar to Neptune.

Class R

R class planets are planets that are similar to Mars, R class planets have a dry small
atmosphere, they frequently have signs of once having had liquid water flowing on the surface of
the planet. These R Class planets have similarities to a T class planet in there sessions and
planetary rotation & axis tilt.

Sub-Classes
Class Ra; These are R class planets that are even more similar to a T class planet, they
have thicker atmospheres, geologically active, & has flowing water on its surface. Theoretically
this sub-class would be half way between a T and R class planet.

Class S

A S class planet is a planet that is similar to Saturn, S class planets are similar to Saturn,
they are Gas Giants they are usually about the size of Saturn or larger, they also frequently have a
large ring system stabilized by shepard moons, theoretically any type of gas giant could have a
ring system stabilized by shepard moons.

Class T

The T class of planets or Terrain Class planets are that are similar to Earth, they have
atmospheres, a varied Climate, Geologic activity & ecosystems.

Class U

The U class of planets are planets that are similar to Uranus.

Class V

The V class of planets are planets that are similar to Venus, V class planets are similar to
Venus, they are hot planets, volcanically active, & their atmosphere is usually a thick Carbon
Dioxide atmosphere with a atmospheric pressure that is usually over 20 times the earths.

Sub-Classes
The Sub-class is a small letter next to the capital letter of the planet class (Example;
Class Re Planet) these denote that there are similarities to other planets classes.

d, This is a special sub-class it only relates to V class planets, it has similarities to the D class of
planets.

e, This letter indicates a planet has similarities to T class planets to the extent of a thick
atmosphere, geologic activity, and flowing water, (also weather patterns?)

r, This letter indicates a planet has similarities to R class planets, a good example would be a Vr
class planet this planet would have a thinner atmosphere, as well as possible frozen water at its
polar caps if it has any, as well as V class features as very geologic activity.

t, A planet with this letter denotes a good capability to be terraformed in to a planet similar to a T
class planet.

Terms

Star - A star is a large body, a ball of gas, in space that burns a fuel source usually hydrogen that
provides light and warmth to a solar system with planets, if there are any.

Planet - A planet is any large spherical body that orbits a star, there is also what is classed as a
rouge planet this is a planet that was ejected from its original star system by ether natural forces
or unnatural forces(ie intelligent interaction).

Asteroids - Asteroids are irregularly shaped bodies that orbit a star in belts, groups, alone, or
around another body that orbits a star.

Moons - A moon is any planet or asteroid that is in orbit around a Planet orbiting a star

Astronomical unit (AU) is the average distance between the earth and the sun--about 93 million miles (150 million kilometers). This unit is used to measure distances within the solar system.

Light-year is the distance light travels in one year--about 5.88 trillion miles (9.46 trillion kilometers). Astronomers use this unit to measure distances outside the solar system.