A zoomed in view of Astraea, a Z5V star located approximately 22 billion light years away, and the surrounding nebula
Class Z stars, or Z-type stars are very massive, hot, bright and rare stars in the universe, for a galaxy the size of the Milky way with billions of stars, only 3 of them are Z-type stars. The closest star of this class is over a million light years away. These stars also emit powerful stellar winds and flares. They are generally confused with Class ΔM Stars, however, unlike them, these stars are much smaller, emit a much vivid pink glow and have much shorter lifetimes.
Z type star compared to O star and our Sun
Z-type stars are very hot, they have surface temperatures ranging from 70,000°C, to over 1,500,000°C in the largest stars. Since they are so hot and bright, they burn their fuel very rapidly. They can also fuse heavier elements than Iron (but not heavier than Astatine) and also elements that stars don't normally fuse, such as Lithium, Beryllium and Chlorine.
These stars are also very massive, around 150-3000 solar masses, 20-550 solar radii, and ranging in brightness from 30 million, to over 8 billion solar luminosities depending on the star's size and spectral type.
These stars have very short lifespans, they live for only 5,000-100,000 years, for comparison, the oldest civilizations are around 5000 years old. They would expand into red megagiants 3 times bigger than Stephenson 2-18 and explode into hypernovas, eventually collapsing into a black hole.
These stars would have a bright neon pink color, as they are so hot they emit shorter wavelenghts of light, in fact, the wavelenghts they emit can be so short sometimes they emit ionizing radiation that can expose any organism to deadly doses of radiation within 2 AUs and very powerful stellar winds that can completely strip away an atmosphere as thick as Venus' atmosphere. Habitable zones in these stars are on the order of thousands of AU, to even several light years depending on their size. This, combined with their very short lifespans, makes life around them virtually impossible.
This is the last non-metric prefix star class.
| Spectral Type | Solar luminosity
(L☉) |
Solar radius
(R☉) |
Solar masses
(M☉) |
Temperature
(K) |
|---|---|---|---|---|
| Z0V | 8,000,000,000 | 550 | 3,000 | 1,500,000 |
| Z1V | 6,863,000,000 | 440 | 2,500 | 1,300,000 |
| Z2V | 4,650,000,000 | 390 | 2,000 | 1,000,000 |
| Z3V | 2,500,000,000 | 310 | 1,700 | 800,000 |
| Z4V | 1,230,000,000 | 230 | 1,350 | 698,000 |
| Z5V | 500,000,000 | 160 | 1,000 | 430,000 |
| Z6V | 230,000,000 | 100 | 750 | 250,000 |
| Z7V | 100,000,000 | 70 | 500 | 176,500 |
| Z8V | 67,000,000 | 45 | 340 | 100,000 |
| Z9V | 30,000,000 | 20 | 150 | 70,000 |
Note: Some rare Z-type stars have special properties that may not fit this list
Second note: At temperatures this high, the difference between celsius and kelvin is almost negligible
| Star Classes |
|---|
| Main Sequence
Dwarves Holes Other |