A reddish supergiant star, 660 light-years from Sol, it is over a billion kilometers in diameter. Prior to stabilization it was a variable star, varying in magnitude from 0.3 to 1.2 over a period of about 7 years, averaging about 0.70. The surface is extremely variable in luminosity and structure, changing slowly but dramatically over time. The core of this star has concentric layers of different elements each of which are themselves fusing. Without artificial intervention, the core of this star will fuse to iron and collapse, creating a supernova explosion.
Betelgeuse was partially stabilized by Sun Miners during the late Establishment period. At first very large amounts of material were removed from the outer envelope, reducing the pressure on the core, and slowing down the rate of fusion somewhat; however this could only prolong the life of the star by a few thousand years.
More recently transapient conversion tech has been used to cause artificial fusion in the core regions, which prevents the star from collapsing. Although the details are not known, it may be possible for the archai to stabilise this star for the foreseeable future by continually producing enough energy to prevent collapse - in short by producing a continual, slow, controlled explosion using conversion weapons.
This vast and luminous but very cool and diffuse star is surrounded by a number of sunminer habitats and several highly specialised ai clades. Sunminers and other stellar engineering clades have been offering rejuvenation / stabilisation projects for centuries. But now everybody plans to buy Emple-Dokcetic shields instead, when they become available. The whole volume is now becoming heavily Empledokcetised (either as insurance in case the sunminer ultratech devices suffer catastrophic collapse, or maybe just aesthetic or cultural reasons) - more worries for the neighbouring empires.
Supergiant - Text by M. Alan Kazlev A very large (10 to 1000 times the diameter of Sol), extremely luminous star in the uppermost part of the H-R Diagram. Supergiants generally result from hot bright O and B class stars exhausting their hydrogen and moving off the main sequence. Supergiants rarely last more than several millions of years. Betelgeuse, Deneb, Rigel A, and Mu Cephei are all supergiants.