Algok is a double star system included in Galactic Neighborhood as one of the pre-included star system. It contains a B-Class main sequence star and an evolving M-Class subgiant. It is the analogue to Algol.
The primary star of the Algok system is actually the smallest of the pair. Algok A is still in the main sequence, yet it is supposed to have a shorter life than Algok B. Algok A has a radius 5 times that of Kerbol and has a mass over 10 times that of Kerbin's sun. Based on its spectral type and size, Algok A appears to be 5-10 million years old.
Algok A is a rather dense star. While not as dense as neutron stars like Osiris, Algok A still is much heavier than its red companion. It takes only a matter of hours for Algok A to orbit the system's center of mass (aka Barycenter). Such mass to outweigh a larger star means that this blue star has an abundance of heavy elements in its core, probably going all the way up to Sulfur. This would mean Algok A is close to fusing Iron and becoming a supernova.
Algok B is quite different from its luminous companion. This is a red subgiant star nearing the end of its lifespan. Algok B's outer layers are expanding into space, reducing its gravity and density. Algok B cannot keep its outer layers for being pulled away by the higher gravity of Algok A. Its mass is not too different than that of Algok A, but Algok B is nearly twice the size as its B-Class companion. This makes it one of the largest stars in this mod.
Because of this M-subgiant being very old, Algok B can put out only a fraction of the light Algok A can. This makes the system and eclipsing binary. When the larger and dimmer Algok B transits Algok A, the binary star's apparent magnitude can greatly drop. It takes about 2-5 Kerbin days for Algok B to revolve around the Algok barycenter, but that slow speed doesn't keep it round. Extreme tidal effects from Algok A tear off much of the red star's bloated outer layers. This actually disorts Algok B into a near-egg shape.
The Algok binary system appears to defy stellar physics and knowledge of how stars form. Both stars have different ages, which should be impossible. Nearly all orbitally stable binary stars formed together and are the same age. But Algok A is less than 10 million years old, while Algok B is older then Kerbol. Why are these even a binary system?
It's possible that Algok B was once a secondary member of another binary star system. The larger member became a red supergiant and went supernova about 500 million years ago. Algok B was catapulted into the now-collapsing nebula and happened to settle into a binary system with one of the first stars in the nebula: Algok A. They would have approached about 6-10 million years ago.
The situation that both stars are in now makes several scenarios for how the Algok system will die. It's possible that Algok A will explode after accumulating too much material from Algok B. However, this only happens with white dwarf stars and not blue main-sequence stars. Another outcome is that Algok A will remove the shell of gas from its companion but not explode.
Algok B would be left as a white dwarf. Then, when Algok A becomes a red supergiant, two things can happen. The white dwarf could collide with Algok A and cause a collision-based supernova. But a more likely outcome is that Algok B would suck up huge amounts of mass from the dying Algok A. The tiny white dwarf will explode in a Type 1 supernova. Later, if it survives, Algok A will also go supernova.