The image of R Sculptoris obtained in the submillimetric wavelengths with the ALMA interferometer shows an evident spiral structure, which connects the star to the outer dust shell by which it is surrounded [ALMA / M. Maercker et al.]

R Sculptoris, the Dying Giant That Draws Spirals in the Sky

During the AGB phase, Sun-like mass stars disperse large amounts of matter into space, enriching the interstellar medium with elements such as carbon, indispensable to the chemistry of life. R Sculptoris, a star in the final stages of its existence, is a magnificent example of this enrichment process, based on a series of cyclical mass ejections, which created a complex envelope of gas and dust

R Sculptoris is a Sun-like mass star, but in a much more advanced evolutionary stage than the Sun. Let’s just say it’s not far from kicking the bucket, astronomically speaking. It is a red giant surrounded by a gorgeous “cinerary urn” of dust and gas, which it itself expelled during paroxysmal spasms. This dust is 90% amorphous carbon, that is, non-crystalline carbon, and 10% silicon carbide molecules (SiC). The percentage of carbon in the stellar atmosphere has exceeded that of oxygen (C/O = 1.4), and this qualifies R Sculptoris as a carbon star.