2.3 Nebula Classification

Created by Captain Kate Banninga on 15 Feb 2015 @ 12:41pm

Nebula Classification

A nebula is an interstellar cloud of dust, gas, and plasma, where star formation usually occurs.

At some point, the Federation introduced a new system to classify nebulae. The new system first assigns the nebula a letter designation based upon its general composition. If the nebula has any unusual quirks, it is assigned an additional number designation. For example, a Class F2 Nebula is a Dark Nebula that contains disruptive electromagnetic radiation.




Nebula Class A – Emission


Emission nebulas are large clouds of ionized plasma where star formation usually takes place. They are illuminated from within by groups of young stars that form in H II Regions within the nebula.


Composition: Hydrogen, helium, oxygen
Average Size: 100 - 5,000 ly
Average Temp.:10 - 20 K
Lifespan: 1 - 2 million years
Color: Red, green, blue
Example: Lagoon Nebula, Veil Nebula

Pictured: Krai’jih’na Nebula

Nebula Class B – H II Region


An H II region is a large stellar nursery, typically located inside an emission nebula. Over the duration of its lifespan, an H II region can give birth to thousands of stars. Gravimetric forces by the larger stars will eventually disperse the nebula and leave behind a star cluster similar to the Pleiades.


Composition:Hydrogen, helium
Average Size: 20 - 2,000 ly
Average Temp.: 10.000 K
Lifespan: 1 - 2 million years
Color: Red, pink
Example: Eagle Nebula

Pictured: Cone Nebula

Nebula Class C – Bok Globule


While an H II region can span light years and contain dozens of stars in varying stages of development, Bok Globules are dense clusters of dust and gas where star formation actually takes place. They commonly result in binary and trinary star systems.


Composition: Hydrogen, helium, carbon
Average Size: 1 ly
Average Temp.: 3 K
Lifespan: 1 - 2 million years
Color: Black
Example: NGC 281, NGC 1999, BHR 71

Pictured: IC 2499

Nebula Class D – Reflection Nebula


Reflection nebulas are large clouds of dust that reflect light from nearby stars. The nearby stars are not usually hot enough to cause ionization, but are bright enough to make the dust visible. Star formation can occur within a reflection nebula.


Composition: Hydrogen, carbon, iron, nickel
Average Size: 100 ly
Average Temp.: 25,000 K
Lifespan: 10 million – 10 billion years
Color: Bleu, purple
Example: Trifid Nebula, Witchhead Nebula

Pictured: Pleiades Cluster

Nebula Class E – Planetary Nebula


Despite the name, planetary nebulas have nothing to do with planets. They are, in fact, the final stage of life for most stars, developing when a star is no longer able to sustain nuclear fusion. As the star’s core contracts, it ejects ionized gases into space, creating a planetary nebula. This plays a crucial role in the evolution of the galaxy, for the process returns material to the interstellar medium.


Composition: Carbon, oxyen, nitrogen, calcium
Average Size: 1 ly
Average Temp.: 10.000 K
Lifespan: 10.000 years
Color: Orange, green, blue
Example:Ring Nebula, Hourglass Nebula

Pictured: Cat’s Eye Nebula

Nebula Class F – Dark Nebula


Dark nebulas are a type of large molecular cloud. The cloud cores are completely invisible to the naked eye, and are be undetectable aside from microwave emissions from the molecules within. Dark nebulas have strong magnetic fields that create considerable gravimetric forces in and around the nebula. Stars and astrophysical masers can form deep inside dark nebulas.


Composition: Hydrogen
Average Size: 200 ly
Average Temp.: 7 K
Lifespan: 1 - 2 million years
Color: Black
Example: Coolsack Nebula, Snake Nebula

Pictured: Horsehead Nebula

Nebula Class G – Supernova Remnant


When a massive star reaches the end of its life, it explodes in an immensely powerful supernova. This event blows the entire star apart, leaving in its wake a remnant nebula that expands into the interstellar medium.


Composition: Ionized hydrogen, oxygen
Average Size: 3 ly
Average Temp.: 10 million K
Lifespan: 1 million years
Color: Varies; typically orange, blue
Example: Tycho’s Remnant, 1987A

Pictured: Crab Nebula

Nebula Class H – Nova Remnant


Nova remnants are similar to supernova remnants, only much smaller on all levels. They are also much more common.


Composition: Ionized hydrogen, oxygen
Average Size: 0.5 ly
Average Temp.: 5.000 K
Lifespan: 300 years
Color: Varies; typically blue, orange
Example: RR Poctoris

Pictured: T Pyxidis

Nebula Class I – Solar Nebula


While most stars form within emission nebulas, there are exceptions to the rule. When a young star forms elsewhere, gravimetric forces gradually attract a disk of dust and gas that flatten to form a new star system that includes planets and asteroids.


Composition: Hydrogen, helium, oxygen
Average Size:100 AU
Average Temp.: 150 K
Lifespan: 2 million years
Color: Yellow, orange
Example: Panak

Pictured: A generic solar nebula

Nebula Class J – Wolf-Rayet Nebula


A Wolf-Rayet nebula forms when strong stellar winds cause a Class O star to rapidly lose its mass. The dispersed mass forms a nebulous halo around the star.


Composition: Helium, carbon, oxygen
Average Size: 0.5 ly
Average Temp.: 25.00 – 50.000 K
Lifespan: 1 - 2 million years
Color: Bleu
Example: NGC 6888, NGC 3199

Pictured: Gamma Velorum

Nebula Class K – Inversion Nebula


Inversion nebulas are rare, highly unstable nebulas created by plasma strings. They typically burn out after a few years.


Composition: Ionized plasma strings
Average Size: 200 AU
Average Temp.: 10.000 K
Lifespan: 5 – 10 years
Color: Pink
Example: Lukkaris Nebula

Pictured: Marayna’s Nebula

Additional Subtype Classifications


Type 1 - Protomatter
A nebula that contains amounts of protomatter.

Type 2 - Disruptive
A nebula that contains disruptive electromagnetic radiation.

Type 9 - Shadow
An ultra-dense nebula with constituent compounds that create sensor shadows. Prolonged exposure is detrimental to humanoid nervous systems.

Type 10 - Deuterium
A nebula that contains deuterium.

Type 11 - Argon
A nebula that contains argon. Thetazenon, fluorine, and sirillium can also be present.

Type 13 - Mutara
A nebula that contains high levels of static discharge and ionized gases; renders shields and sensors inoperable.

Type 16 - Protostellar
A nebula still in its formative stages. Has high levels of particle flux.

Type 17 - Sirillium
A nebula that contains amounts of sirillium.




This information comes from the website of Star Trek the Final Frontier.


Categories: Information Databank