London: Using the full power of the Very Large Telescope Interferometer (VLTI) at ESO’s Paranal Observatory in Chile, a team of astronomers has recorded sharpest view ever of dusty disc around an ageing star, suggesting that discs around ageing stars are similar to those around young ones. As they approach the ends of their lives, many stars develop stable discs of gas and dust around them.
These discs resemble those that form planets around young stars. Till date, astronomers have not been able to compare the two types, formed at the beginning and the end of the stellar life cycle. Michel Hillen and Hans Van Winckel from the Instituut voor Sterrenkunde in Leuven, Belgium targeted an old double star lying about 4000 light-years from Earth in the southern constellation of Vela (constellation)
This double star consists of a red giant star, which expelled the material in the surrounding dusty disc, and a less-evolved more normal star orbiting close to it. “By combining light from several telescopes of the Very Large Telescope Interferometer, we obtained an image of stunning sharpness. The resolution is so high that, for comparison, we could determine the size and shape of a one euro coin seen from a distance of 2,000 km,” said Jacques Kluska, team member from Exeter University in Britain.
The inner edge of the dust ring, seen for the first time in these observations, corresponds very well with the expected start of the dusty disc. The team found that discs around old stars are very similar to the planet-forming ones around young stars.
Whether a second crop of planets can really form around these old stars is yet to be determined but it is an intriguing possibility. “The observations open a new window to study the physics of these discs as well as stellar evolution in double stars,” Winckel said.
