Ap and Bp Stars
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Basic Information

An Ap Star or Bp Star are like normal Class A or Class B Stars, but with very peculiar spectra, implying abnormal chemical/elemental composition. Ap Stars have far less iron than other stars of their class, and both Ap and Bp stars instead have above average amounts of rare elements like chromium, europium, neodynmium, plutonium, praseodymium, promethium, and/or strontium. These elements are very rare in stars, and extremely short lived in general thanks to their relatively short half life. This suggests that some ongoing process continues to replenish these elements, or else they would have all ceased to exist in the stars long before we built telescopes good enough to spot them.

One possible explanation is that these stars may actually have concentrations of other extremely rare super-heavy elements, possibly ones we've never even seen before, such as Flerovium, Unbihexium, or Unbinilium. These super-rare elements may then very slowly break down into the other rare elements detected, allowing them to be replenished fast enough to be seen in their current state.

The unusual elements seem to be concentrated in specific "abundance spots" on the stars surface.

They have stronger than normal magnetic fields. Most Ap and Bp stars rotate much more slowly than is normal for their class, but some Ap stars instead rapidly oscillate, and are known as roAp stars.

See Also:

Class A Star
Class B Star
Przybylski's Star - the first Ap star classified as such, and still a contender for the title of the most peculiar star in the cosmos
Stellar Classification


2. Video: Sci Show

Game and Story Use

  • The fun here lies in coming up with some sort of crazy explanation for the abundance spots.
    • Maybe a huge precursor space fleet was intentionally crashed into them, and those rare elements were part of the FTL drive? It could have happened all across the galaxy when a AI rebellion or deliberate computer hacking took control of the flight computers on the ships.
    • Maybe fiery space whales nest in them, and the chemicals in their spectra are the spoor or eggs of the creatures.
  • The abundance spots could be the source of the phlebotinum of your setting, or could be the cause of some sort of energetic effect like how superman has powers dependent on the color of the star he's near.
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