Located approximately 400 light-years from Earth in the constellation Cetus, the red giant star Mira A is currently the focus of intense astronomical study. Recent observations have revealed that Mira A is expelling its outer layers at a velocity greater than previously recorded, marking a notable mass-loss event.
A team led by Theo Khouri from Chalmers University of Technology in Sweden discovered two large, asymmetrical clouds of material expanding from Mira A. These clouds were observed using the Very Large Telescope and ALMA telescopes in South America during 2015 and 2023. The resulting structure resembles a cosmic heart, with a cloud of dust at the edges and gas filling the interior.
This newly identified cloud contains approximately seven times the mass of the Sun, which is several hundred times more than the typical mass-loss ejections from Mira A. The unexpected density of this cloud surprised researchers. “We know that stars like Mira lose mass as they age, but we did not expect it to happen in such large and sudden bursts,” stated Khouri, the lead author of a paper detailing these observations.
Understanding Mira A’s Behavior
Mira A is classified as a variable red giant, with brightness fluctuations resulting from regular pulsations of its surface. As it nears the end of its life cycle, Mira A periodically ejects material into space, contributing heavy elements that are essential for planet formation and possibly for life.
Khouri noted that the expanding cloud surrounding Mira A is significant as it may influence its companion star, the white dwarf Mira B. “We will keep monitoring the expanding cloud around Mira A, as it is becoming so large that it may start to affect its companion star,” Khouri explained.
Insights into Stellar Evolution
The recent outburst from Mira A offers valuable insights into the evolution of stars within the asymptotic giant branch. The team suggests that if such ejection events are periodic, they could occur every 50 to 200 years. The mass loss from Mira A, estimated at about one Earth mass every decade, contributes to the enrichment of the interstellar medium.
Khouri and his colleagues propose two scenarios to explain the recent mass ejection. The first scenario accounts for the total mass ejected so far, while the second suggests a more explosive event possibly linked to an X-ray outburst around the same time.
The Future of Mira A
Eventually, Mira A will shed its outer layers entirely and transition into a slowly cooling white dwarf star. Until that time, its mass-loss events will continue to provide critical data on the life cycles of stars similar to Mira A.
As red giants like Mira A approach their end, they offer a glimpse into the future of our own Sun, which will undergo a similar transformation in billions of years.
This article was produced by NeonPulse.today using human and AI-assisted editorial processes, based on publicly available information. Content may be edited for clarity and style.
