Char is located in a binary star system. The primaries, a class VI F0 sub dwarf orbiting an M8 irregular variable, bombard the planet with cosmic rays. The planet's extremely elliptical orbit has a volatile affect on its geography. Eris and Ate are Char's two large natural satellites, each being purplish in color and having a diameter of more than 1000 kilometers. It also appears to be orbited by a debris field. Char is located within the Zerg Quarantine Zone.
Char is tectonically active and all 18 of its mountain chains are volcanic. Not surprisingly, large areas of Char are covered with lava.
When the planet's orbit swings close to the stars vast molten areas can form on its sunward face. Conversely as its orbit takes it farther away cooling may cause large temporary islands to form.
Despite the volatility Zerg tunnels may be pervasive under 40% of the surface four years after the Brood War.
The acrid air has a high oxygen and sulfur content and is laced with ash, and the average temperature is 48 degrees centigrade with very low humidity. An unprotected Terran may survive on the planet, however uncomfortably. Despite the conditions small pockets of liquid water exist on the surface.
Char has thick layers of ash which can wreak havoc on sensitive equipment and can also cover hazards such as magma pools. Clouds of ash form which are thick enough to block the view of the stars, making navigation difficult. In addition, fluctuating magnetic fields render magnetic compasses unreliable.
The magma, driven by powerful tectonic activity, often seeps to the surface. The harsh tectonic conditions can cause horrifying firestorms which unrelentingly burn across the plains; the tectonic activity can result in pyroclastic flows traveling down mountains at speeds of over 100 miles per hour and with temperatures in excess of 800 centigrade (1470 °F). Temperatures are sometimes so intense that entire sections of its surface become liquefied.
Char is one of the richest resource nodes in the sector, as the tectonic activity continually uncovers deposits of minerals and geysers of vespene gas. Additional resources become accessible when the planet is farthest away from the stars. The temporary islands formed from the magma are replete with minerals.
The surface of Char can reach such extreme temperatures that mineral deposits melt, forming rivers which can last months before finally hardening. Mineral-laden pathways are then created, protruding from the obsidian landscape, serving as both landmarks and rich mining fields.
For more information see Char on the parent site