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. |
| Nebula Classification |
Nebula Class A • Emission Nebula
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Hydrogen, helium, oxygen 100 - 5,000 ly 10 - 20 K 1 - 2 million years Red, green, blue Lagoon Nebula, Veil Nebula Krai’jih’na Nebula |
A nebula is an interstellar cloud of dust, gas, and plasma, where star formation usually
occurs.
In the year 2400, 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.
occurs.
In the year 2400, 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.
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. |
Nebula Class B • H II Region
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Hydrogen, helium 20 - 2,000 ly 10,000 K 1 - 2 million years Red, pink Eagle Nebula Cone Nebula |
While an H II region can span light years and contain dozens of stars in varying states 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. |
Nebula Class C • Bok Globule
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Hydrogen, helium, carbon 1 ly 3 K 1 - 2 million years Black NGC 281, NGC 1999, BHR 71 IC 2499 |
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. |
Nebula Class D • Reflection Nebula
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Hydrogen, carbon, iron, nickel 100 ly 25,000 K 10 million - 10 billion years Blue, purple Trifid Nebula, Witchhead Nebula Pleiades Cluster |
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. |
Nebula Class E • Planetary Nebula
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Carbon,oxygen,nitrogen,calcium 1 ly 10,000 K 10,000 years Orange, green, blue Ring Nebula, Hourglass Nebula Cat's Eye 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. |
Nebula Class F • Dark Nebula
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Hydrogen 200 ly 7 K 1 - 2 million years Black Coalsack Nebula, Snake Nebula Horsehead Nebula |
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. |
Nebula Class G • Supernova Remnant
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Ionized hydrogen, oxygen 3 ly 10,000,000 K 1,000,000 years Varies; typically orange, blue Tycho's Remnant,1987A Crab Nebula |
Nova remnants are similar to supernova remnants, only much smaller on all levels. They are also much more common. |
Nebula Class H • Nova Remnant
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Ionized hydrogen, oxygen 0.5 ly 5,000 K 300 years Varies; typically blue, orange RR Pictoris T Pyxidis |
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. |
Nebula Class I • Solar Nebula
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Hydrogen, helium, oxygen 100 AU 150 K 2,000,000 years Yellow, orange Panak A generic solar 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. |
Nebula Class J • Wolf-Rayet Nebula
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Helium, carbon, oxygen 0.5 ly 25,000 - 50,000 K 1 - 2 million years Blue NGC 6888, NGC 3199 Gamma Velorum |
Inversion nebulas are rare, highly unstable nebulas created by plasma strings. They typically burn out after a few years. |
Nebula Class K • Inversion Nebula
Composition Average Size Average Temp. Lifespan Color Example Pictured |
Ionized plasma strings 200 AU 10,000 K 5 - 10 years Pink Lukkaris Nebula Marayna's Nebula |
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.
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.
Additional Subtype Classifications