Title: Starfire
Description: From back cover of Bantam Spectra paperback May 2000:

THE END DRAWS NIGH

The year is 2053, and Earth has barely recovered from the Alpha Centauri supernove that destroyed much of the planet's infrastructure.  Now the supernova's residual effect -- a storm of high-energy particles -- is racing towards Earth, and an international effort has been launched out of the Sky City space colony to save the planet.  But the controversial plan -- to build a giant protective shield for Earth -- is falling dangerously behind schedule.  A series of unexplained murders has disrupted the Sky City workforce, so much so that a brilliant but monstrous criminal has been enlisted to track down the Sky City killer.

Then comes more startling new.  Evidence indicates that the original supernova was caused deliberately, and that the lethal particle storm will arrive sooner than anyone expected.  But who -- or what -- tried to destroy the Earth?  And will the answer come in time to save it from its final apocalypse?
Subjects: Twenty-first century, Supernovae, Fiction, Fiction, science fiction, general