Dramatic dying star blows smoke rings in unique celestial show
A strange star just got even stranger. In the midst of its death throes, the star V Hya has been belching out a series of rings and plumes of materials, in a pattern never before seen from a dying star.
V Hya is located about 1,300 light-years from Earth, in the constellation of Hydra. As a carbon-rich red giant star, it’s currently in its final stages of life, shedding its outer layers ahead of a final outburst to become a white dwarf wrapped in a nebula.
But V Hya seems to be taking an unusual route to that end. Peering closer at the star using the ALMA radio telescope, astronomers realized that V Hya isn’t releasing its material in a uniform way as would be expected – instead, it’s blowing out a series of "smoke rings." The team spotted six rings in all, which appear to have been produced over the last 2,100 years or so – a very short time on a celestial scale. These rings are forming a warped disk around the star, which the team gave the questionable moniker of DUDE, for “Disk Undergoing Dynamical Expansion.”
But those rings aren’t V Hya’s only outburst. The astronomers also noticed huge hourglass-like clouds being thrown above and below the star, which are expanding at speeds of 864,000 km/h (537,000 mph).
Even before these new discoveries, V Hya was a very fascinating star. It’s previously been found to fire off Mars-sized balls of plasma every eight and a half years, with astronomers chalking up this bizarre behavior to an unseen neighbor, like a neutron star or white dwarf. If this compact companion orbits V Hya every 8.5 years, it would periodically swing through the star’s swollen outer atmosphere, slurp up some material then shoot it off into space.
Altogether, these features make V Hya an absolutely unique object, which could have much to teach astronomers about the life and death of stars.
“The end state of stellar evolution – when stars undergo the transition from being red giants to ending up as white dwarf stellar remnants – is a complex process that is not well understood,” said Mark Morris, co-author of the study. “The discovery that this process can involve the ejections of rings of gas, simultaneous with the production of high-speed, intermittent jets of material, brings a new and fascinating wrinkle to our exploration of how stars die.”
The research was published in The Astrophysical Journal.