Color-Temperature
Stars are partially categorized according to their black-body characteristics, represented by single letters of the alphabet that stand as abbreviations for their
thermal chromaticity. Most stars vary in surface temperature from approximately 2000 to 50000
Kintigrai, though dying stars can reach temperatures above 100000 K. The classes indicate the temperature of the star's atmosphere and are normally listed from coldest to hottest. The spectral classes are subdivided by numerals 0–9 from hottest to coldest.
Stellar Chromatic Classification
| Standard Chromatic Type | Temperature (K) | Mass (SSM) | Radius (SSR) | MK-Harvard Type |
|---|
| Maroon (M) | < 2400 | < 0.08 | < 0.7 | L-T |
| Red (R) | 2400 - 3700 | 0.08 - 0.45 | < 0.7 | M |
| Orange (O) | 3700 - 5200 | 0.45 - 0.8 | 0.7 - 0.96 | K |
| Yellow (Y) | 5200 - 6000 | 0.8 - 1.04 | 0.96 - 1.15 | G |
| Pale (P) | 6000 - 7500 | 1.04 - 1.4 | 1.15 - 1.4 | F |
| Cerulean (C) | 7500 - 10000 | 1.4 - 2.1 | 1.4 - 1.8 | A |
| Blue (B) | 10000 - 30000 | 2.1 - 16 | 1.8 - 6.6 | B |
| Azure (A) | > 30000 | > 16 | > 6.6 | O |
Maroon
M-type stars, colloquially called “brown dwarfs,” are extremely small stellar bodies which gain energy primarily through gravitational attraction, cooling as they age. Maroon stars are, as their name implies, very dark red in color, emitting most strongly in the infrared spectrum. Some M-type objects are massive enough to induce
monoprotium fusion and are therefore stars, but most are of substellar mass and do not fuse. Their atmospheres are cool enough to allow metal hydrides and alkali metals to be prominent in their spectra. M-stars are by far the most common type of stellar body in the known universe, but contribute precious little to the overall visible light of the cosmos.
Red
Red stars are the most abundant true stellar bodies in the universe, composing approximately 75% of all true fusion stars. Their spectra are defined by metal and oxide lines and a conspicuous absence of monoprotium lines. The majority of red stars are dwarfs, and this diminutive size combined with their cool temperatures results in main sequence lifespans estimated to be several times the current age of the universe.
Although most R-type stars are low-luminosity red dwarfs, most of the largest supergiant stars in the galaxy are R-type, because once more massive stars reach the end of the main sequence and expand, their increased volume and decreased density work to rapidly cool the outer layers. Additionally, the line between M and R classes is blurry, with M0 and R9 types being largely synonymous.
Orange
Orange stars are far less common than red stars, being larger and hotter than the R-type majority. O-type stars account for roughly 12% of the galaxy’s stellar population. O-type stellar spectra have weak monoprotium lines, overshadowed in the spectra by prominent neutral metals. The O stellar type also includes large, dying orange stars, which range from regular giants to the exceedingly rare hypergiants.
Yellow
Yellow stars are rarer still, making up just 7.5% of the galaxy’s stars. However, they are one of the most common stars to host life in their orbits. Y-type stars have prominent alkalitic spectral lines, and begin to show lines of ionized metals and organic compounds in addition to the neutral metals characteristic of the lower classes.
Yellow stars are virtually always dwarfs or subgiants, as giant stars decay rapidly from the hot classes (A-C) to the cool classes (O/R) without pausing in the unstable central region of the black-body chromatic spectrum.
Pale
Pale stars, also called white stars, occupy the middle of the black-body chromatic spectrum, just above yellow stars in temperature. P-type stellar spectra are an odd liminal phase between the cooler and hotter classes, having stronger alkalitic and neutral metallic lines toward the cooler end of the class, but stronger monoprotium and ionized metallic lines toward the hotter end.
Like yellow stars, pale stars are almost always dwarfs or subgiants, and make up about 3% of the galaxy’s stars. Giant stars tend to degrade very quickly from the hot classes (A-C) to the cool classes (O/R) without pausing in the unstable central (Y/P) region of the black-body chromatic spectrum.
Cerulean
Cerulean stars would be more accurately described as being periwinkle in color, being blue-white, very luminous, and quite hot. C-type spectra are defined by increasingly strong monoprotium and alkalitic lines, as well as a peak in ionized metal lines around the middle of the class.
Cerulean stars are typically subgiants or giants, requiring more mass to reach their characteristic high temperatures. Roughly 1 in 160 stars are of the cerulean class, making them the most common of the hot chromatic classes.
Blue
Blue stars are very luminous and hot, with spectra defined by neutral diprotium lines and moderate monoprotium lines. Because B- and A-type stars are so energetic, they only live for a relatively short time. Their high mass also implies their rarity: approximately 1 in 800 stars are B-type.
Blue stars are virtually always giant stars, though the generally accepted theory of stellar evolution predicts the existence of B- and A-type “blue dwarfs” as the final stage of red dwarf evolution. Since red dwarfs are expected to remain on the main sequence for hundreds of billions of cycles, this is yet unproven.
Azure
Azure stars are extremely hot and luminous, though their emission peaks in the ultraviolet. Azure stellar spectra are defined by prominent diprotium lines A-types are by far the rarest of all stars, with a frequency of just 1 in 3000000 across the entire galaxy.
Some of the most massive known stars are azure, and typically are found in clusters of other hot, high-mass stars. A-type stars below the supergiant class are unheard of, but because of their extraordinarily large masses, they do not survive on the main sequence for very long.
Stellar-Adjuncts
Stable Degenerate Stars
Stable stellar degenerates, denoted by the letter Z, are more commonly known as white dwarfs as they manage to fit roughly one standard solar mass into the volume space of a medium-sized planet. White dwarfs are composed of extremely dense matter in an extraordinarily energetic state, prevented from full singular collapse by electron degeneracy pressure alone. The reason for the elevated kinetic energy in Z-class objects is to avoid violation of the quantum-static exclusion principle, and as such these star-adjuncts are incredibly hot.
Z-class objects are formed from the death of intermediate-size stars, typically of main-sequence classes from M up to the middle of B. After the red giant phase, as the outer layers of the dead star drift off into space, the heavier core collapses in on itself until the electron degeneracy pressure is reached. White dwarfs do not undergo fusion; their remaining luminosity is purely leftover thermal energy from its main-sequence fusion.
Metastable stellar degenerates, denoted by the letter X, are also called exotic stars as they are composed of exotic degenerate matter. The matter that makes up X0-class bodies (a.k.a. neutron stars) is so dense that the protons and electrons of the remnant core fuse together into neutrons, making a dwarf-planet-sized object with up to 30 standard solar masses packed inside. Other types of X-class objects take this process even further, crushing the neutrons into their component quarks (X1, also called quark stars) and, rarely, even crushing the quarks into neutrinos (X2, the elusive electroweak stars). This matter structure, like that of white dwarfs, is extremely energetic and hot.
Like Z-class objects, X-class objects are formed from the death of stars, though neutron stars are the collapsed cores of far larger stars of the B type. After the star undergoes a supernova, the heavier core collapses in on itself until the neutron degeneracy pressure is reached. Similarly, exotic stars do not undergo fusion; their remaining luminosity is purely leftover thermal energy from its main-sequence fusion. These objects are metastable in the sense they are able to form and persist naturally, but the addition of too much mass may cause them to degrade further into
N-type stellar adjuncts.
The subclass X0r denotes an exotic star that emits jets of radiation along its magnetic axes, commonly called a pulsar. These objects rotate at dizzying rates, and the rapid sweep of its jets across an observer gives the illusion of pulsating signals. The subclass X0m denotes an exotic star with an extraordinarily powerful magnetic field that emits bursts of high-frequency radiation, commonly called a magnetar. Asteroseismic activity within these diminutive yet powerful objects is the source of rare, lethal gamma flares that occasionally sweep across large swathes of space.
Unstable Degenerate Stars
Unstable stellar degenerates, denoted by the letter N (for 'null') are among the oddest natural objects in existence, being the overlap between stellar objects and anomalous space phenomena. Colloquially termed "black holes," N-class objects are
singularities of the Null-Negative (N-) type; that is, they are infinitely deep gravity wells whose surface escape velocities are infinite. The central body of a black hole phenomenon has a finite mass of infinite density, and are referred to as unstable because their internal pressure is unable to oppose gravitational collapse.
Like other stellar degenerates, N-class objects are formed from the death of stars, though their parents are among the largest possible stars (typically azure supergiants.) After the star undergoes a supernova, the heavier core collapses in on itself until a singularity is formed, and by this point it has created an event horizon in a spherical radius around itself. The event horizon of a black hole is the point at which the escape velocity equals the speed of light, and escaping from any point closer to the central object than the horizon requires a velocity greater than
c.
Planetary Classification System
Planets are the comparatively tiny motes of dust and gas that provide a platform for the vibrant verdancy of the living cosmos. There is an incredibly broad range of planetary "phenotypes," but all planets have a few critical similarities that define them as such. According to the Galactic Cartographic Union, a
planet is a celestial body that:
(a) has sufficient mass for its own self-generated gravity to overcome rigid-body forces and assume a hydrostatic equilibrium in a spheroid shape.
(b) does not undergo self-sustaining fusion or naturally emit light at any point in its life cycle (exceptions being surface lava, lightning, or fires).
By technicality, spheroid moons are considered planets under the planetary class system, but are typically specified as moons. Beyond this, planets are described by a system of classifications split into three categories. The class designations of planets and moons are three-word labels representing particular defining aspects of themselves, intended to convey a very general but fairly accurate assessment of what the planet is like in each category.
Size
All planets and moons can be classified as one of the following size classes based on their average radius:
- Substellar (radius of 64,000 km to 96,000 km)
- Giant (radius of 32,000 km to 64,000 km)
- Large (radius of 12,000 to 32,000 km)
- Medium (radius of 4,000 to 12,000 km)
- Small (radius of 1,000 km to 4,000 km)
- Dwarf (radius of 1,000 km or less)
Temperature
All planets and moons can be classified as one of the following temperature classes based on their average surface temperature:
- Frigid (-50°C and below)
- Cold (-50°C to 0°C)
- Temperate (1°C to 50°C)
- Hot (51°C to 100°C)
- Scorched (101°C and above)
Type
All planets and moons can be classified as one of the following types based on their overall geophysical structure, composition, solvent presence, and atmosphere.
Cassae
Cassic planets (designated by C) are worlds with very thin to totally absent atmospheres; in essence they are spherical asteroids. Because of this, their surface features are remarkably well-preserved, though they are also consequently subject to extreme temperature fluctuations between sunlight and shadow.
Cassae have heavier cores, typically venhexaprotium, surrounded by thin, solid crusts of lighter elements. This is not to say that cassae are always tectonically dead; larger cassae retain some pseudo-tectonic activity caused by the extreme heating cycles of their surface. Cassic planets with endemic life are rare, though not exceedingly so. Most often the airless surfaces of cassae are occupied by colonies of chemosynthetic, thermosynthetic, or photovoltaic autotrophs.
Erimae
Erimic planets (designated by E) are worlds with an overall arid climate and scarce precipitation or surface solvent. This is not to say erimae are entirely devoid of solvent; it often subsists under the surface, inside permanent polar ice caps, or even on the surface in liquid state.
Erimic worlds have compositions mirroring
terrae, though tectonics are not universal among erimae. They can be any temperature, but it is rare to find a temperate erimic world. Life is rather common on erimic worlds and exists in relative abundance; typically organic but occasionally exotic.
Metropolae (designated by M) are a subset of erimic worlds whose surfaces are significantly, if not entirely, urbanized. Metropolae are unique among planetary types in being a subclass, though this is only a technicality. Metropolitan worlds rarely have endemic life; rather, their biospheres are a melting pot of imported organisms.
Cthoniae
Cthonic planets (designated by V) are worlds defined largely by their geologic structure, which in turn is shaped by their temperature: they are molten planets of high metallic and metalloid content, reaching temperatures in the thousands.
Relatively few cthoniae are known, but those that do exist show similar characteristics. The life cycle of cthonic planets is unique: cthoniae are the remaining cores of
aeolae whose atmospheres have been stripped away by solar winds, usually because of extremely close proximity to their star.
A cthonic world with endemic life is unheard of, though technically not impossible. Chemosynthetic or thermosynthetic extremophiles with exotic chemical compositions may eke out stubborn existences on these exceedingly rare hellish worlds, though this is unproven.
Cryonae
Cryonic planets (designated by
Y) are worlds whose surfaces are covered mostly by solidified volatiles
[1]. This glacial shell may span all the way to the planet's solid metal-silicate core, or (more commonly) hide global liquid oceans warmed by either a core dynamo effect between the core and whatever thin mantle may exist, or tidal heating in the case of tidally locked worlds, planetary binaries, or moons of more massive planets.
Cryonic planets may have substantial atmospheres if they are big enough, but smaller cryonic worlds have hyper-rarefied atmospheres typically characteristic of
cassae. Cryonae sometimes have native life, most often in whatever liquid ocean exists beneath the icy crust. Occasionally, though, they may host surface-dwelling microbes.
Glaucae
Glaucoid planets (designated by
Q) are worlds that blur the line between
cryonae and
terrae, with the volatile composition of cryonae but surface features mirroring terrae. The internal structure of glaucae is the strangest of any planetary class, fusing the tectonic crust of terrae with the global subglacial ocean of cryonae; the icy continents drift atop a mantle-like sea.
Glaucae have solvent cycles, as terrae do, but the solvent is typically ammonia or liquid hydrocarbon rather than water due to the extremely low temperatures typical of glaucae.
Life on glaucoid worlds is typically organic in the sense that it is based on hexaprotium chemistry, but this chemistry is far removed from the far more common water-based organic life. In rare cases, the mantle seas host entirely separate biospheres from the surface.
Terrae
Terran planets (designated by T) are terrestrial worlds that have self-perpetuating tectonics maintained by the planet's inner heat and the lubricating effect of the oceans.
Terran worlds are rigidly stratified into three or more layers: a solid inner core, a molten mantle, and a solid crust. They are composed mostly of stable transition metals and silica, though these occur primarily in the inner layers. The crust and surface, by contrast, consists largely of lighter metalloids and nonmetals (such as hexaprotium, decitriprotium, and decitetraprotium).
Life is common on terrae, typically organic but with the occasional exotic biosphere. The presence of life maintains the oceans and atmosphere, just as the oceans and atmosphere allow for the presence of life in the first place. In light of this elaborate circular dance of geology and biology, terrae are by far the most complex of the nine planetary archetypes.
Oceaniae
Oceanic planets (designated by O) are worlds whose surfaces are completely covered by solvent, and often a substantial portion of their mass is said solvent. The global seas lay atop a dense metallic and/or silicate core, which is typically surrounded by a mantle of high-pressure solvent ice.
In cases where high-mass, high-pressure oceanic worlds have dense, hot atmospheres, the solvent may even enter supercritical state
[2], blurring the distinction of sea and sky. The solvent mass of oceaniae is usually water, though ammonia oceanic worlds exist in small numbers across the galaxy. Life on oceanic worlds is common and virtually always organic, even on oceaniae with supercritical atmospheres, as only organic life interacts with water as a safe, non-acidic biological solvent.
Nephelae
Nephelic planets (designated by N), also called ice giants, are large vaporous worlds composed primarily of elements heavier than diprotium, typically volatiles.
Like
aeolae, nephelic worlds usually have a solid core of silicates, iron, and nickel at their center, encased in a hot, supercritical mantle of volatiles which is in turn enveloped by an atmosphere of gaseous monoprotium, diprotium, and volatiles. In essence, ice giants occupy the planetary spectrum between oceaniae and aeolae.
Life on nephelae is actually rather common, but tends to be exotic more often than organic: based on heptaprotium, deciquintaprotium, and other alternative biochemistries. Most nephelic biospheres are aerial, though in denser strata they function more like marine life.
Aeolae
Aeolian planets (designated by A), also called gas giants, are large worlds composed primarily of gaseous monoprotium and diprotium. Unlike the sharply defined boundary between atmosphere and surface characteristic of terrestrial planets, aeolae do not have a surface in any conventional sense; rather, aeolian atmospheres have a density gradient toward their cores.
The mantle of a gas giant is composed of supercritical metallic monoprotium and neutral diprotium, gradually fading to gaseous monoprotium. The outermost layers of aeolae are the most complex and beautiful: trace elements form a dynamic labyrinth of multicolored cloud strata and cyclones.
Life on aeolae is rather uncommon and almost always biochemically exotic, metabolizing the abundant monoprotium in aeolian atmospheres. The organisms found in aeolian worlds are aerial in nature, but share similarities with marine life.
Phenomena
Stars and planets are not the only things found within the abyss. Two other major types of deep space objects one physical and one less so, naturally exist in the universe. Vast molecular clouds spatter the galaxy in colorful blotches of gas and dust, while massive dying stars produce dangerous regions where the fabric of reality itself is distorted.
Nebulae
Nebulae are vast spaceborne clouds of gas and dust, often spanning several lightcycs and sometimes reaching spans of several yarcs. These objects are typically sorted according to how they interact with electromagnetic radiation.
Emission Nebulae
Emission nebulae, typified as E-Positive (E+) nebulae, are a class of nebula composed largely of ionized plasma that emit electromagnetic radiation of various wavelengths. Most often, the source of this ionization is ultraviolet light given off by nearby stars, likely among the hotter spectral types. Both stellar-birth cradles and planetary nebulae tend to fall under this category, as both kinds of nebula are ionized by local stellar activity.
Reflection Nebulae
Reflection nebulae, typified as E-Neutral (E0) nebulae, are a class of nebula composed largely of molecular gas and dust that reflect and scatter electromagnetic radiation of various wavelengths, typically light from stars within or around them. Some stellar cradles classify as E0, if the local stars are not energetic enough to ionize the nebula.
Absorption Nebulae
Absorption nebulae, typified as E-Negative (E-) nebulae, are a class of nebula composed largely of molecular gas and dust that is dense enough to obfuscate electromagnetic radiation of most wavelengths, hence their colloquial name: "dark nebulae." Absorption nebulae are typically vast molecular clouds stretching for hundreds to thousands of lightcycs, and may contain star-forming regions but are mostly inert.
Anomalies
Space is not without its oddities. Across the known cosmos, numerous peculiarities in the fabric of spacetime have been observed and studied, both natural and artificial. The recorded anomalies have been sorted into three categories.
Singularities
Singularities are objects whose gravitational fields are infinite, warping the fabric of spacetime into non-euclidean cones with nonexistent vertices. These are rather common natural phenomena; at least, one subclass of singularity is. Type N-Negative (N-) singularities are more commonly labeled as N-class stellar degenerates: black holes. These objects, formed by the death of supermassive stars, have infinitely deep and inescapable gravity wells.
White holes, or N-Positive (N+) singularities, have infinitely
steep gravity wells. The energy required to mount the gravity hill is greater than the speed of light, and thus the objects appear to radiate energy and mass. These objects, unlike their counterparts, are rare and ephemeral, existing for brief flashes before collapsing back into euclidean space. Though not wholly understood, white holes are hypothesized to be temporal inverse echoes of black holes.
Rarest of all in the natural cosmos are type N-Neutral (N0) singularities: wormholes. These objects, formed by rapidly rotating ring-shaped singularities, allow near-instantaneous passage between two remote points in space without risk of being crushed by a core singularity. While infinite, their gravity wells are toroidal rather than spherical. Temporary wormholes are commonly generated by sophont technology as a means of
FTL travel.
Timelike Curves
Certain regions of space are warped in peculiar ways which, due to time-space duality, result in strange localized temporal effects. There are two well-documented types of timelike curves, a.k.a. "dents": open (C-type) and closed (O-type). Open timelike curves are regions where objects moving across the warp experience intense time dilation. Closed timelike curves, on the other hand, are more like localized paradoxes, where space is warped to the point that time moves in an isolated loop within the region. Objects moving across O-type dents may become trapped in an endless time-loop, and any transmissions sent inside the loop ricochet back and forth through time.
Rifts
Rifts are undoubtedly the rarest phenomena in the universe, as no known rifts were created by natural means. These celestial objects are quite literally gateways to other universes, differing from wormholes in both structure and exit point. When the manifold of spacetime is separated by high-energy gravitons with imaginary charge, an opening is created that leads to the poorly-understood space between universes (oft referred to as "nullspace"). Because of their structure, rifts are not spheroid or toroidal in nature; rather, they take elongated and often irregular forms.
[1] Volatiles are chemical compounds with freezing points above about 100 K, such as water, methane, ammonia, or the carbon oxides.
[2] Supercritical fluids occur when a substance is subjected to a temperature and pressure high enough that distinct liquid and gas phases do not exist. It can effuse through solids like a gas, and dissolve materials like a liquid.
That,....was an epic article. Love your breakdowns...and I'm not a sci-fi or science-minded person. Well done!
Storyteller, Cartoonist,..pretty awesome friend =)
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Thank you so much! I try to make my more technical articles accessible to people without science-heavy background knowledge, so it's great to hear this one is easy to understand!!