Astronomers reveal in a new study how the disc of material surrounding a dying star possesses uncanny similarities to the disc of planet forming material enshrouding infant stars, which means that these two discs of stellar material both have similar compositions.
When stars are at their final stages of their lifespan, they tend to produce discs of gas around them since stellar winds can swirl these gases before the dying star turn into a red giant. Now, these discs are also observed in young stars, as this material is also conducive for forming planets.
With the help of powerful telescopes such as the Very Large Telescope Interferometer (VLTI) at the Paranal Observatory in Chile, a team of scientists were able to conduct a comparison between two different types of discs that focuses on a distinct "double star" known as IRAS 08544-4431.
This double star is located some 4,000 light years away, in the constellation Vela, which can only be viewed in the Southern Hemisphere. This double star is composed of a red giant and a younger star orbiting near its region. According to author of the study, Jacques Kluska from Exeter University in the U.K., with the combination of light from several telescopes inside the Very Large Telescope Interferometer, the image obtained was remarkably sharp, equivalent to a 150 meter diameter telescope would view.
Using a special technique, the VLTI removed the other stars in view to isolate the double star and to examine closely the fundamental qualities of IRAS 08544-4431. Scientists discovered that the most observable feature is this distinct ring around the stars where the inner area corresponds to similar dust discs that are closer to the stars, that would also disappear when exposed to radiation of nearby stars.
According to author of the study, Michel Hillen of the Instituut voor Sterrenkunde in Leuven, Belgium, the team was surprised to see a fainter glow from this small accretion disc within the companion star. The star was indeed double, but observations revealed its companion directly, where the team detected the inner regions of this very distant star system.
Even if these two stellar disc materials are made from the same dust and gases, researchers were still unclear if it is possible that planets could form around a dying red giant. This new study aims to examine further the physics of these discs along with the stellar evolution seen in double stars or binary systems.
This new study is published in the journal Astronomy & Astrophysics.