Extended Morgan-Keenan Spectral Classification System

The Extended Morgan-Keenan Spectral Classification System is the system used to measure and classify stars in the OSISCV Continuation Wiki Universe, based on their luminosity and and Temperature. It is largely based on Ziegfried-Creation’s DogePro Simulation experience stars, (go check out their YouTube channel!)

Warning: This page is very long. Please read at your own risk .

## Types

the 20 types and subtypes in decreasing luminosity and temperature are,

### P types - Pink Hypergiants

they are the highest classification and their surface temperature can reach 1,000,000 kelvins, their sizes, 75-100x higher than the sun’s and can be a few tens to 100 billion of times brighter than the sun. They have masses up to 5000x that of our sun and are short lived, lasting no more than 100,000 years and dying in powerful Hypernova explosions.

### H types - Magenta Hypergiants

They can be between 1000-2500 times the sun’s mass, their sizes, 50-75 Suns, and they can be a few hundred million to several billion times brighter than the sun. They last less than 500,000 years and die in less intense hypernovas. They are not to be confused with C-H type carbon stars which are also shortened to H. Their temp is 750000 Kelvin to 500000 Kelvin

### U types - Purple Hypergiant or extreme Wolf Rayet

U types are a hotter version of Wolf Rayet stars, having temperatures 250,000 Kelvin to 500,000 Kelvin. They last no more than 1 Million Years, and die in hypernovas. Their luminosities range from a few ten millions to hundreds of millions of times more luminous than our sun.

### W types- Wolf Rayets

Wolf Rayet or W type stars are hot but not as bright as the previous 3 types, and their sizes can vary. Smaller wolf rayets occur when a red supergiant or hypergiant with an initial mass of 30-60 solar masses shrinks rapidly over thousands of years. Larger ones occur when a massive o type, 60-150 solar masses leaves the main sequence before becoming a Luminous Blue Variable Hypergiant although it may evolve back into one Their temperature varies from 30,000 Kelvin to 250,000 Kelvin. They have 3 subtypes, WN (hydrogen lines) WNC (a mix of hydrogen and Carbon lines) WC (Carbon Lines) and WO (Oxygen lines) with WNC being a mix of WN and WC.

### O types- Deep Blue Giants

O types are the most massive conventional star and some of the brightest, though not as bright as their distant cousins, the W types. Their masses vary from 17-150 solar masses, sizes from 4.9-20 Suns and their luminosities from 20000-2,500,000 that of the sun. In addition just like w types, their evolutions are also varied depending on their mass, Smaller O stars under 30 solar masses, will expand into red supergiants or hyper giants, then go supernova or hypernova, although before the explosion they may evolve back to a blue, white or yellow supergiant. Mid mass o types, from 30-60 solar masses after the red supergiant or hyper giant phase, shrink into wolf rayets for a few thousand years before they go supernova or hyper nova. The most massive o types from 60 to 150 solar masses, will become wolf rayets, then Blue hyper giants or luminous blue variables, but may evolve back into wolf rayet stars depending on the metallcity of the star. Typically, they last 2.5-12 Million years.

### N-types- Blue Giants

N type stars are technically a subtype of b type stars but only the supernovable B types (6.84-17 solar masses can be classified as one. They live for 15-100 million years before they turn into red supergiants and go supernova. Spica is an example of a N type star. The temperature varies from 20000 K to 30000K.

### B types- Light Blue Main Sequence

B type star’s masses vary from 2.5-17 solar masses and the most massive are classified as N type stars. Their sizes vary from 2.2-7.5 times that of our sun. Their life expectancy is from 15-500 million years Larger B types will expand into red supergiants and go supernova as they die. Smaller stars under the supernova mass limit of 6.84 solar masses will expand into red bright giants , undergo a helium flash causing them to shrink into smaller yellow giants, then will expand into Non supernovable Red Supergiants before they shrink into white dwarfs, which will cool into black dwarfs over time. A example is the B5V star Benetash, also known as Eta Ursae Majoris, and Alkaid.

### A, I, and E type- White Main Sequence

a type stars have masses of 1.7-2.5 solar masses, their size from 1.6-2.2 Suns, and their temperature from 7600 K to 9700 K. They will become red bright giants when they die, shrink into a red clump star, than enter the Agb phase, when the star will randomly go through size changes before it shrinks into a white dwarf. It has 2 subtypes, the I types, and the E types that straddle the border between A and F types. The E types are not to be confused with elliptical galaxies, which are abbreviated as E. They usually live for about 500 million years to 2 billion years. They are not to be confused with white dwarfs.

### F types- bright yellow dwarfs

F types are are at the brighter end of yellow stars. They have masses of 1.1 to 1.7 Solar masses, their sizes vary from 1.1-1.6 Suns, and their temperature from 6000-7600 Kelvin. They live from 2 billion to 10 billion years. When they die, the will go through a similar evolution of an A type star, except less brighter than their counterparts, and becoming white dwarfs which will cool down after trillions of years in a black dwarf.

### G types- Yellow Dwarfs

G types are stars similar to the sun and are usually similar in mass and size (0.85-1.1 SM or SR) They have a temperature from 5200K to 6000 K. When they die they will go through a similar stage like a A, I, E and F type stars, only that during the Helium flash, they will be orange giants, not yellow giants.

### K and Z types- Orange Dwarfs

K and Z type stars are technically the same type but are divided to show the difference between higher mass k types and lower mass ones. Their masses and sizes vary from 0.6-0.85 Suns, and their temperatures from 3900 K to 5200 K. They have a red giant phase but no AGB or helium flash. They usually live for 20-70 Billion years

### M types- Red Dwarfs

red dwarfs have masses and sizes of 0.1-0.6 solar masses . Unlike A-K/Z stars, most of them shrink into blue dwarfs before the white dwarf stage, but the most massive ones can become red subgiants. They live for 70 billion to 8 trillion years.

### V-types- Ultracool Dwarfs

these are a subtype of M types but they deserve their own section. These vary from 0.076-0.1 suns in both size and radius. The temperature varies from 2000 K to 2600 K. Just like their most of their more massive brothers, they will shrink blue dwarfs before they become white dwarf. They are not to be confused with K/Z type stars because of their orange color. Lifespan 8-12 Tyr

### L, T, and Y types- brown dwarfs

they are not exactly stars but are somewhat closer to planets. They have masses between 13-76 Jupiters (0.013-0.076 Solar masses) but are similar in size to Jupiter (10-12 earth radius in diameter). They will actually cool from an initial star-like state before going to act like a planet. They have 3 subtypes , L (starlike) T (Methane) and Y (Cool).

### Q types- Sub Brown dwarfs

similar to brown dwarfs . Masses overlap with super Jupiter planets. Mass from 8-13 Jupiters but size is similar. The difference between Q types and Super Jupiters is their formation process because Q types form more like stars than planets. They are not to be confused with neutron stars, also abbreviated as Q.