For decades, astronomers believed that Eta Carinae was a massive double star that shines 5 million times brighter than the Sun was unique, and nothing like this was found in the Milky Way galaxy or beyond.
But now scientists know that This Carina, located about 7,500 light-years from Earth, is not alone. A study of the Hubble Archives and the Spitzer Space Telescope found five snapshots of Eta Kiel's twins in neighboring galaxies, astronomers said at a meeting of the American Astronomical Society in Kissimmee, Florida.
In addition to scale, this keel's most distinctive feature is the expanding shell of gas and dust — the result of a massive eruption in the 1840s, which has thrown the equivalent of more than 10 times the mass of the sun into space.
What caused the eruption on Eta Carina remains a mystery, but scientists used clouds of dust to find five more supermassive stars that have experienced similar explosions.
"We are looking for rare evolutionary stages in very rare stars - the rarest of rare objects," Astronomer Rubab Khan told the NASA Goddard Space Flight Center in Greenbelt, Maryland.
“Twins” This carina is very far, up to 26 million light years - too far for telescopes to view individual stars. Khan and his colleagues developed an optical infrared model to “hunt” for such stars. The technique compares the amount of ultraviolet and visible light that is obscured by a dust cloud when heated by dust caused by light reabsorbed on large and medium infrared waves.
Then scientists tried to find similarities in the amount of dust that is observed around Eta Carina. Two similar stars were found in the galaxy M83, located approximately 15 million light-years, one each in NGC 6946, M101, and M51, located between 18 million and 26 million light years from us.
Khan said that every twin Eta Carinae could be a supermassive star buried in gas and dust, equivalent to a weight of five to ten times the mass of the Sun.
"This carina is not unique ... It happens in nature. However, this is very, very rare. This is the first time we can say quantitatively how rare this carina is," said Khan.
The discovery is expected to help scientists better understand how massive stars form, evolve and die.
The study was published in the Astrophysical Journal Letters on December 20 and presented at the AAC conference.