 The Sygnus Star System was the name applied to DM+38 2885 by the captain of the W-Y Explorer: Sygnus during the first survey of the region in the year 2160 A.D. Sygnus Prime is the largest component of a binary star system; the companion is designated Seargento. The two stars lie roughly 38.8 light years from Earth, near the very far tip of the American arm. Five major bodies and several smaller chunks make up the star system.
The star is classified as a G8 VI main sequence star, with a diameter of over 635,900 kilometers and a mass .47 times that of Earth's sun. Its average luminoscity is .145 of Sol, with a Stellar Effective temperature of 4520 degrees K. The star's absolute magniturde of +6.71. As a subdwarf, it is unusual that Sygnus Prime possesses any planets at all, and even odder in that its single planet is actually considered a garden world known simply as Sygnus. It has as companion star as well, the M-class dwarf known as Seargento.
Classified as an M0 V, Seargento has a diameter of 746,496 kilometers. It has a mass of Sol and an average luminoscity of .04 Sol. The Stellar Effective Temperature is roughly 3500 degrees K and has an absolute magnitude of 12. Although Seargento is the brighter of the two suns and is generally designated as the primary body of the system, Seargento is actually the companion star. They share a mutual orbit around a common point at an average seperation of 2 AU. Sygnus, the only planet in the dual system, orbits Sygnus Prime.
The planetary system of Sygnus and its companion are fairly young and is classified as Population I. There is only one true planet in the sytem: Sygnus, which orbits Sygnus Prime within the proper life zone distance to produce near-habitable conditions, is only a 'garden world' by comparison with such hell-holes as Fury-161 and other less hospitable locations. Numerous planetoidal chunks in a highly eliptical orbit testify to the break up of a planet sized intruder into the system eons ago. Some of these chunks have proven quite valuable and support a fair-sized asteroid mining operation. However, the main focus of attention in the system is Sygnus the site of the thriving Weyland-Yutani colony.
But for an accident of nature, Sygnus would probably have developed as another of the worthless rocks so common in explored space. Supporting a rather thin atmosphere and scant free water Sygnus' classification as a 'garden world' is due to exceptional conditions in a single region of the planet known as the 'twilight-zone'. The twilight zone is a relatively thin band between the light and dark sides of the planet roughly two-hundred kilometers wide. These special conditions have shaped the planet's role in colonial exploration.
Sygnus (the colony world) orbits Sygnus (the star) at roughly .36 AU, with a minimal eccentricity. These factors give Sygnus a rotational period of 36.26 standard days; due to the regularity of its orbit and minimal axial tilt, however, seasonal changes within this month-long "year" are almost unnoticable. The planet's orbit places it squarely in the stellar life zone.
Sygnus has a mass of .31 Earths and a planetary diameter of 11,041 kilometers, giving it a circumfrance of 34,683.3 kilometers. Owing to the low density and mass, gravity is only .612 G; which gives the world a surface escape velocity of 9.46 kps. The axial inclination of 3 degrees, 18 minutes, and 12.5 seconds. Sygnus has no natural satellites.
Given the low density and surface gravity, Sygnus has a low atmoshperic pressure of roughly .597 atmospheres. The planet retains elements with molecular weights of 17 and up and an atmospheric mix comprised of Nitrogen, Oxygen, Carbon Dioxide, and various trace elements. Though similar in some respects to Earth, this atmospheric envelope is somewhat different in its percentages of these different components; with an oxygen content of over 10 percent, the partial pressure of oxygen (0.059 atmospheres) is barely enough to support unprotected humans.
Although Sygnus' low mass and close orbit cause it to experience a tidal lock to its primary, the complex interplay of the twin stars in their mutual orbits cause considerable libration effects, giving a significant band of the so-called 'twilight-zone' - something of a day/night cycle with an average period of 22 hours of daylight followed by a nine-hour night. However, this varies considerably according to the observer's location in the relation to the terminator line and the exact position of the two suns in their orbits around one another. Moreover Seargento does give the 'darkside' of Sygnus a faint reddish illumination during those periods when the planet and the star are in conjunction.
The thin atmosphere does very little to diffuse the stellar radiation. Temperatures tend to be high on the dayside and in the twilight zone during daylight hours, dropping radically on the darkside or at night. Extremes of temperature produce violent wind storms moving across the twilight zone from the cold night side into the warmer day side; as the warm air rises it moves back across the terminator producing some limited precipitation across the habitable band.
Sygnus lacks a significant radiation belt, which leaves the surface exposed to the unpleasently high levels of lethal radiation poured out by the two stars. A further risk is posed by the periodic flares emitted by Seargento, which, like most M-class dwarfs, is somewhat unstable in output. Luckily these flares are rather infrequent (occuring on the order of once every 25 or 30 standard years), but when they do occur, they cause significant increase in radiation and in stellar magnitude. During flare periods, the Sygnus colony is subject to several weeks of quarentine due to the inability of of most interstellar ships to find a safe haven from the radiation threat. The oribital facilities around Sygnus are also shut down and evacuated during this quarentine period.
During flares, the temperature on Sygnus can climb by as much as 60 degrees C over normal limits causing hazardous conditions for anyone not able to take shelter in underground sheilded facilities. The radiation problem also limits communications to line-of-sight under the two suns, and during flares, it causes an almost complete breakdown in all but the most high-powered signalling systems.
Sygnus' hydrosphere covers just under 10 percent of the planet's total surface area. A significant portion of this hydrosphere is locked up in the form of ice-sheets on the night side. The hydroshpere is composed of water but it has an unusually high salt content that renders it largely useless to human colonists without extensive desalinization.
The planet possesses a fairly usual mix of terrain types, the most common variety being extensive desert uplands. The most prominant terrain feature on the planet is a gigantic crater located in the twilight zone region not far from the planetary equator. Planetographers have postulated that a rouge world plunged through the system several hundred thousand years ago, but was broken up as a result of tidal stresses generated from to close a passage between the twin stars. The planetary detritus remained as a highly elliptical asteroid belt, which remains a prominant part of the system to this day. The belt lies at a sharp angle from the solar ecliptic, but twice each 'year' (once every 18.13 standard days) Sygnus moves through this zone. At some point the planet's history, it was subjected to a strike by a particularly large plenetoidal fragment, a 'dinosaur killer' of truely epic proportions.
Sygnus, like Mars, maintains a high iron content within the soil of the upper strata of crust. The entire planet gives off a reddish glow in certain lighting conditions. However, on most locations on the surface of Sygnus resembles Mars in almost every respect.
The purpose and structure of the Weyland-Yutani colony on Sygnus is tree fold, hence the name 'Trinity'. Firstly, the orbital docking stations above Sygnus allow vessels to dock for service and refueling as well as cargo handling operations. The largest of these stations is Vandermere which serves as the primary starport facility - handling all traffic to and from the surface. Several other stations maintain a geo-synchronous orbit around Sygnus and serve a variety of other specialized functions - mainly scientific in nature.
Secondly, Trinity Station is a small installation consisting of a platoon sized force of United States Colonial Marines and also serves as offices for Colonial Administration officials. This station is considered extra-territorial to the remainder of the colony and Weyland-Yutani's claims to the planet. It is common knowledge among the marines that posting to an assignment like Trinity Station is a severe form of punishment and illdeserved for any self respecting soldier.
The third, and most important, component of the Trinity plan is the Trinity Colony installation itself. Trinity had started as many other colonies had - in prefab above ground bio-domes offering shelter from the outside environment. However, due to the flare activity and quarentine requirements of Sygnus, the prefab colony soon took on a different appearance. It soon grew deeper into the surface with many of the rock piles giving way to paved areas covered in sheet lead while the installation itself grew further and further underground.
Mining operations had burrowed out large quantities of rock and strata deeper and deeper into the planet. Naturally these man made caverns were a haven for those people and machinery seeking to avoid the deadly radiation periods above ground. Much of Trinity Colony has been fabricated underground over the years utilizing the winding tunnels as their guide. As the colony grew, so did the network of underground passages and service tunnels. Many additional areas had been carved out in anticipation of further growth of the colony, but remain dormant while awaiting that eventuality. Much of this unused space is currently used to store records and spare equipment. The constant temperatures and low level of enviromental changes make these storage areas ideal for this specialized purpose and are sealed from the main colony by way of pressure doors.
Other notable locations along the twilight-zone have been developed, all be it only slightly, as outposts for prospectors and 'wild-cat' treasure hunters. These installations are normally prefabricated and disposable, most often being left behind when a prospecting group moves on to a new location.
Portions of this system data have been taken from the Traveller 2300 Colonial Atlas (pages 22 & 23), GDW 1988 - originally written by J. Andrew Keith. No infringment on the rights of the original work are intended.
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