Unexpected Spiral Structure Found Around Red Giant Star R Sculptoris
Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered an unusual spiral structure around R Sculptoris, a red giant star. The astronomers say the spiral structure was probably created by a hidden companion star orbiting the red giant.
Matthias Maercker, lead author of the study from the Argelander Institute for Astronomy, said in the announcement, "We've seen shells around this kind of star before, but this is the first time we've ever seen a spiral of material coming out from a star, together with a surrounding shell."
Red giants go through periodic thermal pulses where explosive helium burns in a shell around the core. The mass of red giants is also reduced by stellar wind. The astronomers think a hidden companion star shaped the wind from R Sculptoris into the spiral structure discovered by ALMA. This video shows a computer simulation of how the material is distributed around the star. Take a look: