Altair
Via Fraser Cain at Universe Today, I've been reading a US National Science Foundation (NSF) press release about imaging the surface of a star. The star in question is Altair which is part of the Summer Triangle. Altair is a bit shy of twice the mass of our Sun, is about 10 times as luminous and rotates about three times per Earth day rather than our Sun's leisurely 25-30 day rotation rate. This rapid rotation means that the star is pretty oblate.

Aritists impression of Altair (left) based on the actual interferometric image of Altair (right). CREDIT: Zina Deretsky, National Science Foundation and Ming Zhao (University of Michigan)
The observations were made at infra-red wavelengths using an interferometric system on top of Mt Wilson in California. This technique connects the output of several telescopes and allows astronomers to simulate the effect of having a telescope as large as the distance between the telescopes. This only helps in resolution (the sharpness of the image) and doesn't help with sensitivity (the gray scales), but for a bright star like Altair it does the job. Radio astronomers have been using this technique for years to simulate radio telescopes the size of the planet Earth, so it is good to see it being used for other wavelengths.
There is a site with supporting material which links to more images and the Science paper.
Posted in astro blog by Stuart on Friday 01st Jun 2007 (13:18 BST) | Permalink