Astronomers from the Canary Institute of astrophysics was discovered in the Large Magellanic cloud an unusual group of stars with low metal content, surrounded by a cloud of iron dust. As reported by Naked science, in the study were involved in a theoretical model of dust formation in circumstellar shells, and pictures taken by the space telescope Spitzer.
Stars with a mass from one to eight solar is developing along the asymptotic branch of the giants before ending their lives as white dwarfs. It was during this short but important phase of the star expand to an enormous size, and cool, losing most of the mass due to strong stellar winds. Low temperature and high density winds provide the perfect conditions for condensation of dust in their circumstellar shells.
The dust that is ejected by stars during the asymptotic branch of the giants, is important for the life of galaxies, as it contains essential for the formation of new bodies components. In the new study, researchers watched a group of stars in the Large Magellanic cloud. The researchers found that the stars were formed about 100 million years ago and have very little metallov, such as iron, metal and silicon.
In addition, the researchers found that a similar distribution of energy in the infrared range can be obtained only if the iron dust is the main component of the circumstellar shells. It’s unusual for stars of the asymptotic branch of giants. Previously it was known that such stars mainly produce silicates, magnesium and large amount of oxygen and silicon. According to the study, scientists first described a class of stars with surprising spectral properties.