The Red Giant Mira (top left) pushes on his journey through space a kind of bow wave of matter in front (top right), which mixes with the cooler stellar winds, flows backwards around the star and thus forms the huge tail. Illustration: NASA / JPL-Caltech
Reading NASA researchers have discovered a 13-light-long tail behind the binary star system Mira. This binary star system is in the final stages of its life, expelling much of its mass. It moves at such a high speed that the ejected mass forms a tail. Since this can only be seen in the ultraviolet range of the spectrum, it has been overlooked in previous investigations of the starry sky. Mira, also known as Omicron Ceti, was first described more than 400 years ago. However, the ultraviolet tail has just been discovered by astronomers around Christopher Martin of the California Institute of Technology at Pasadena. For this purpose, the research team used the NASA space telescope GALEX, which has been investigating the starry sky in the ultraviolet range of the spectrum for several years.

The fact that the tail was previously undiscovered, Martin Zuflge is mainly due to two reasons. For one, ultraviolet investigations of the starry sky are currently still quite rare. On the other hand, the 13-light-year tail is so massive that local studies by Mira in the ultraviolet region of the spectrum have overlooked the significance of the dust cloud.

The dust at the end of the tail is probably more than 30, 000 years old. The researchers hope to learn more about the dynamics of the formation of new celestial bodies by examining the tail more closely. Dust clouds of dead stars often serve as germs for the formation of new stellar objects.

A refined spectral analysis of the tail should also reveal its chemical composition. In this way, astronomers can find out how the formation of chemical elements has changed in the course of Mira's death. display

Message from NasaNature, Volume 448, page 780ff Stefan Maier


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