Giant bubbles on red giant star’s surface

Astronomers using ESO’s Very Large Telescope have for the first time directly observed granulation patterns on the surface of a star outside the solar system—the aging red giant π1 Gruis. This remarkable new image from the PIONIER instrument reveals the convective cells that make up the surface of this huge star, which has 700 times the diameter of the sun. Each cell covers more than a quarter of the star’s diameter and measures about 120 million kilometers across.