Sirius is the brightest and largest star in near space, located 8.9 light-years from Earth. Terran ships have visited the system but have never approached closer than 1 billion kilometers due to the massive amounts of radiation emitted from the star. Its white-dwarf companion, Sirius B, poses a gravitational hazard for ships that travel in the system. For these reasons, the Terran Defense Force and civilian ships rarely travel to the binary system.
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Sirius A and its white dwarf companion, Sirius B.
Credit: NASA; ESA and G. Bacon (STScI)
The Sirius stars are approximately 280 million years old. Sirius A is an A-class white star about twice as massive as the sun and 25 times as bright. Its companion is about equal in mass to Sol, but with a radius of only 6,000 kilometers. The star was originally a B-class blue giant about 5 times as massive as the sun and entered its red giant phase about 130 million years ago. Any planets that formed early during the system's evolution likely were immolated during Sirius B's red giant event.