The Europa system, located at relative cluster coordinates 03-C, is a solar system with eight planets, five terrestrials and three gas giants, located near the edge of the local cluster. The system's star is a magnetar-type pulsar emitting periodically (every 8.27 seconds with a standard deviation of +/- 0.00012 seconds) in the x-ray and gamma ray spectrum, along with pulses in the UVC, UVA and blue wavelengths. With a radius of eight times that of Sol's star and thirty times its mass, it is one of the densest pulsars with 'habitable' planets. The extremely unstable magnetic field frequently shatters and reforms as part of a randomized polar inversion process, bathing the entire star system in deadly radiation; the electromagnetic interference is enough to damage unshielded electronic equipment, jump drives and scramble RADAR and communications systems.
Chosen by the United Systems Coalition for its strategic placement near several now-defunct Helium-3 deposits and the unique properties of its pulsar, allowing the classified facilities the Coalition built in close orbit to the star, the Europa system served as the home system to the Coalition for centuries (from the Alarei War to the end of the Second Stellar War, during which the seat of the government was moved to XE-52 'Oscar').
A massive asteroid belt between the fifth and sixth planets forms a gigantic ring around the star, named the Hawking Asteroid Field by Coalition astrographers to honor the late astrophysicist and cosmologist.
PlanetsEuropa I: A small rocky planet with no atmosphere, analog to Mercury. The only inhabitants of the planet live in underground mining outposts that extract copper from the rocks. Its extremely close proximity to the pulsar make communication only possible with the shaded hemisphere of the planet, where the electromagnetic interference is weakest. Radiation levels on the surface are enough to deliver a lethal dose in less than a second if one is exposed to them directly.
Europa II: A planet with roughly the same size as Earth but with an extremely thick sulfur-based atmosphere. Thanks to an extreme greenhouse effect, the temperature remains almost constant at 140 degrees Celsius at the equator. It is a primary source of transition metals for the Coalition.
Europa III: A desert world with a thin oxygen atmosphere, barely supportive of human life. Extreme radiation renders living on the surface impossible, although interestingly, the pulsar accounts for only half of the surface radiation; nuclear fallout makes up the remainder. The planet houses the ruins of a long extinct civilization that lived twenty thousand years prior, but their technology level seems to have been limited. The scars of the devastating nuclear war that annihilated them are still obvious.
Europa IV: Right at the edge of the Goldilocks zone, Europa IV is a tundra planet, with temperatures in the equator ranging from 5 degrees Celsius in the summer to -30 in the winter. It has a (barely) breathable atmosphere composed of oxygen-nitrogen with a pressure of 0.74 atm, and the strong magnetic field protects it from a large fraction of the pulsar's radiation, allowing humans to survive on the surface for extended periods of time. Nevertheless, it has relatively few resources, and its primary export is petroleum products. Since the Second Stellar War, the use of hydrocarbons to power the electrical grid of Europa IV has attracted huge corporate conglomerates to invest in the once meaningless world.
Europa V: Europa V is an ice planet twice the Earth's mass and one point five its radius, generating an average surface gravity of 0.9g. Nevertheless, it has been unable to sustain any significant atmospheric pressure, which stays at 30% of Earth's sea-level pressure. This is often attributed to the extremely weak magnetic field, which allows solar wind from the nearby pulsar to strip the atmosphere layer by layer. The atmosphere is composed mainly of nitrogen (89%) with traces of oxygen (4%), ozone (2%), xenon (1%), sulfur hydride (1%), chlorine (1%) and helium (2%).
Surface temperatures vary wildly. During the day, the temperature at the equator averages at -50 Celsius and -90 C in the poles. During the night, the temperature drops to an average of -110 at the equator and -160 near the poles. These extreme variances have forced the planet's fauna to live either within the (radioactive) oceans, or underground.
Surface radiation renders life above the ice impossible. Europa V's surface receives an average of 1,000 rems every day (500 is the lethal dose for humans), and more than 10,000 rems during the pulsar's bursts, which occur randomly throughout the year. In addition, the ice itself is extremely radioactive in areas exposed to the star's light, and the water is radioactive due to the presence of a high concentration of tritium (a radioactive isotope of hydrogen).
Interestingly, liquid water exists on the frozen surface. Intense volcanic activity heats up the radioactive water and pushes it towards the surface, cracking the weakened by the temperature ice during the day. This forms rivers and lakes that freeze during the night.
Each year lasts for 387 days, and each day on Europa V is 40 hours due to its slow rotation around its axis. The length of day and night remain mostly uniform throughout the year, with the longest day being on the 217th day of the year.
Europa VI: A gas giant with 37 moons. Although it had been originally used for Helium-3 mining, extensive use of its resources over three centuries has made extraction of the precious isotope a very costly venture. Very few corporations can afford to operate the facilities inside the atmosphere, which have to venture deeper and deeper into the crushing pressures to reach atmospheric layers with a meaningful Helium-3 composition.
Europa VII: A gas giant with a large ice belt, and a primary source of hydrogen isotopes (deuterium primarily). The facilities for extracting deuterium had been mostly abandoned before the second war, but the fuel shortage has brought with it a spike in deuterium prices, and thus generated interest in the less efficient fuel source.
Europa VIII: A small gas giant composed primarily of radon gas. In visual scans it is often mistaken for the star due to its blinding red glow, a result of the extremely low temperatures and strong pressures: radon emits a bright red radioluminescence under these conditions.