Giant Bubbles on Red Giant Star's Surface
For the first time, granulation patterns on a star other than the Sun have been seen — using the PIONER instrument on ESO's VLT
π1 Gruis is an ageing red giant star, similar in mass to the Sun, but 350 times larger and several thousand times as bright.
This giant has just a few convective cells, each about 120 million km across.
Just one of these granules would extend from the Sun to beyond Venus!
By contrast the Sun has around two million convective cells, each about 1500 kilometres across.
These stars may seem to have very little in common...
... but both will one day bloom into spectacular planetary nebulae, and then fade away slowly as white dwarfs.
π1 Gruis is approaching this stage, but the Sun has about five billion years left to-go!
Transcribed by ESO, translated by —