Artifacts are structures built on stars that provide certain bonuses to the empire owning that star. An empire can only build one artifact in it's life, other artifacts must be captured to use them. All artifacts can attract trade ships, increasing the Empire's wealth.
Wormhole Disruptor[]
This temporarily (on average about half the time) disrupts the wormhole connecting this star to neighbours. This means that it is protected from attacks (though not empire-wide events), and also that it can not launch any attacks.
It can also have the interesting side-effect of splitting up the galaxy into different isolated parts, which can have some nice effects.
Lunar Monument[]
This is just an ego-boost for the ruler of the empire. When built, it removes most of the wealth of the star it was built on. Attracts trading ships.
Research Laboratory[]
This artifact makes the planet research at a massively increased speed. and plays an animation from time to time.
Missile Station[]
Launches fabulous missiles at enemy stars. Fun fact: They can actually hit ships as well, though they never aim at them.
Mind Control Hub[]
Dispatches Mind Control Pods to nearby stars, to convince them to join the cause of the empire who owns the Hub.
Fleet Base[]
Hosts 4 Interceptors, that can launch against any hostile ships (or meteors and etc) that approach. Each interceptor has a white laser that deals 1.0 Laser.
Stellar Forcefield[]
Shields a star providing the equivalent of 3 tech levels of defense, and destroys all hostile projectiles and ships.
Disrupt Launcher[]
Shoots disruptor missiles at hostile stars, destroying them and breaking their connections for a while.
Financial Center[]
Increases wealth of nearby friendly stars. Has a particle effect in the form of coins.
Holy Site[]
Is the holy site of an religion. Makes people around it have a greater chance of following the religion of the Empire that built the artifact.
Sentinel Station[]
This artifact fires orange missiles dealing 1 HP of damage against Space Oddities. Their projectiles can cover the entire map and are mostly fired in bursts of 3 before a cooldown. The sentinel station has actual animation not particles. There is a small glitch that the Sentinel Station will fire on some ships in its own empire but it won’t do any damage.
Imperial Tomb[]
This artifact spawns "ghosts" - dead 4-star-people that had been working for the Empire. After some time, a group of them may swarm out to attack the ship with the highest level in the galaxy.
Weapons Platform[]
This gives a significant boost (equivalent to 2 tech levels) for attacks either against this star itself, or attacks from this star to an adjacent enemy star. It also triggers a fancy animation.
It may also defend from other items, such as missiles or space oddities using a white laser that deals 1.0 damage.