Space Telescope Science
Great balls of fire! The Hubble Space Telescope has detected superhot blobs of gas, each twice as massive as the planet Mars, being ejected near a dying star. The plasma balls are zooming so fast through space that they would travel from Earth to the moon in 30 minutes. This stellar "cannon fire" has continued once every 8.5 years for at least the past 400 years, astronomers estimate. The fireballs present a puzzle to astronomers because the ejected material could not have been shot out by the host star, called V Hydrae. The star is a bloated red giant, residing 1,200 light-years away, which has probably shed at least half of its mass into space during its death throes.
The current best explanation is that the plasma balls were launched by an unseen companion star in an elliptical orbit around the red giant. The elongated orbit carries the companion every 8.5 years to within the puffed-up atmosphere of V Hydrae, where it gobbles up material from the bloated star. This material then settles into a disk around the companion, and serves as the launching pad for blobs of plasma, which travel at roughly a half-million miles per hour. This star system could explain a dazzling variety of glowing shapes uncovered by Hubble that are seen around dying stars, called planetary nebulae, researchers say.