European Southern Observatory | ann1058 | 09 Sept 2010
Milli-arcsecond images of the Herbig Ae star HD 163296 - S Renard et alNew research carried out using ESO telescopes has, for the first time, allowed astronomers to reconstruct a detailed picture of the inner disc of matter around a young star. Stéphanie Renard of the Laboratoire d’Astrophysique de Grenoble and colleagues used the ESO VLT Interferometer to probe the secrets of the star HD 163296.
Young stars are surrounded by discs of dust and gas and scientists believe that it is in these discs that planets are born. Dusty grains in the disc stick to each other to make larger lumps that in turn also aggregate together. This growth is expected to continue until rocky bodies about the size of the Earth are formed.
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No single telescope currently in operation has vision acute enough to study such tiny and distant objects. The size of the region of the disc observed corresponds to 150 million kilometres — about the distance between the Earth and the Sun, but located at 360 light-years from Earth.
These very tiny details have an angular size of around 10 milliarcseconds — equivalent to trying to pick out small features on a road map held up 40 kilometres away. These minute angles are far smaller than any single telescope now operating can resolve.
To be able to image the inner part of the disc of matter close to the star, the team used a technique known as interferometry, in which sophisticated instrumentation combines the light from several telescopes into one observation. This increases the level of detail in the resulting pictures dramatically, although it does have some drawbacks: the results have to be reconstructed using complex mathematical algorithms because interferometry does not produce unambiguous images. But this difficult work is worthwhile as the resulting pictures tease out details far beyond the capabilities of the individual telescopes.
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