First snaps of the face of Altair, a star very much like our Sun

An international team of astronomers have, using a suite of four telescopes, captured an image of the Altair; a star very much like our Sun about 15 light years away.

Washington, June 2 : An international team of astronomers have, using a suite of four telescopes, captured an image of the Altair; a star very much like our Sun about 15 light years away.

While astronomers have recently imaged a few of the enormous, dying, red-giant stars, this is the first time anyone has seen the surface of a relatively tiny hydrogen-burning star like our Sun.

Altair is a speedily spinning "rapid rotator", just like Vega, one of Altair's partners (with the slow-spinning supergiant Deneb) forming the Summer Triangle in the night sky.

Altair spins so quickly, about 300 kilometres per second at its equator, that it's shape is distorted: the star is a full 22 percent wider than it is tall.

"The galaxy is shaped by the effects of relatively rare but powerful hot, rapidly rotating stars. These stars have more in common with Altair than our own sun and understanding Altair will allow us to better understand how these influential stars scattered throughout the galaxy operate," said John Monnier of the University of Michigan, and the lead author on the study in the May 31 issue of Science Express.

For their study, the team used four of the six telescopes at a facility on Mt. Wilson, California, operated by the Center for High Angular Resolution Astronomy (CHARA) at Georgia State University in Atlanta with partial support from the National Science Foundation (NSF).

According to Monnier, the CHARA telescopes were able to make the breakthrough observation because they were outfitted with a novel system, a technology called the Michigan Infrared Combiner, to clean up some of the distortions from Earth's atmosphere.

"For looking at optical or infrared wavelengths of light, the CHARA telescope array has the world's longest spacing between telescopes and therefore the greatest ability to zoom in on the stars," said Hal McAlister, CHARA director and a professor of astronomy at Georgia State.

"Recent advances in fibre optic telecommunication technology made this new combiner possible," he said.

Using the telescopes as an interferometer--a multi-telescope system that combines information from small, distantly spaced telescopes to create a picture as if taken from one large telescope--the researchers captured infrared lightwaves as if from a giant telescope 265 meters by 195 meters in dimension. This is about 100 times the size of the mirror and 25 times the resolution on NASA's Hubble telescope.

"Without the interferometer, the ability to obtain such detailed images would not be possible with today's existing telescopes--or even the planned 30-meter telescopes. The critical component of the CHARA system is the beam combiner which allows the light from the individual small telescopes to be mixed together, which up to now had only been successfully used with radio telescopes such as the Very Large Array near Socorro, New Mexico," said Julian Christou, one of the NSF officers overseeing the research.

According to Christou, the findings are considered significant, as until now, while astronomers could gather tremendous amounts of data from stars, they could not capture images of what the stars looked like.

The researchers further said while the new telescope measurements confirmed the oblong shape, yet it showed slightly different surface temperature patterns than what the models predicted.

ANI