Awesome images of Betelgeuse reveal how explosive red supergiant loses mass


Friday, July 31, 2009

It looks like a catastrophic explosion in the latest sci-fi action thriller but this awe-inspiring image is actually based on the latest state-of-the-art space imaging.

The artist’s impression, inspired by the sharpest ever views of the supergiant star Betelgeuse, reveals an enormous plume of gas almost as big as our own Solar System blasting outwards.

The discoveries, revealed by the latest techniques on the European Space Agency’s Very Large Telescope, could help unravel why the mammoth plasma ball spews out material at such an incredible speed.

It looks like a catastrophic explosion in the latest sci-fi action thriller but this awe-inspiring image is actually based on the latest state-of-the-art space imaging.

The artist’s impression, inspired by the sharpest ever views of the supergiant star Betelgeuse, reveals an enormous plume of gas almost as big as our own Solar System blasting outwards.

The discoveries, revealed by the latest techniques on the European Space Agency’s Very Large Telescope, could help unravel why the mammoth plasma ball spews out material at such an incredible speed.

Almost 1,000 times larger than our sun, Betelgeuse is the second largest star in the constellation of Orion and one of the biggest stars known to man.

The red supergiant is also one of the most luminous stars, emitting 100,000 times more light than the Sun.

For decades, astronomers have struggled to explain how the mysterious red supergiants expel such vast amounts of material. They can shed the mass of the Sun in just 10,000 years.

One theory was that the loss could be shed from areas above the star’s polar caps as they rotate.

But the two teams, who have studied the supergiant with the NACO and AMBER instruments on ESO’s Very Large Telescope, have concluded that it is powerful gas motions within the star that force out the huge mass of gas.

One team captured the sharpest image to date of Betelgeuse using NACO, an adaptive optics instrument, and a ‘lucky imaging’ technique, which combines the sharpest exposures to surpass the accuracy of a long exposure.

The resulting image approaches the theoretical limit of resolution possible with the 8-metre telescope. It is so sharp it could even spot a tennis ball on the International Space Station from Earth.

‘Thanks to these outstanding images, we have detected a large plume of gas extending into space from the surface of Betelgeuse,’ lead researcher Pierre Kervella from the Paris Observatory told the website PhysOrg.

The plume bursts out to at least six times the diameter of the star - about the distance from Sun to Neptune.

‘This is a clear indication that the whole outer shell of the star is not shedding matter evenly in all directions,’ adds Kervella.

Meanwhile, results from AMBER revealed intense up-and-down motion of gas within Betelgeuse’s atmosphere.

Keiichi Ohnaka from the Max Planck Institute for Radio Astronomy in Bonn, Germany, said: 'Our AMBER observations are the sharpest observations of any kind ever made of Betelgeuse.

'Moreover, we detected how the gas is moving in different areas of Betelgeuse’s surface - the first time this has been done for a star other than the Sun.

Combined, the unrivalled observations have led the astronomers to propose that these large-scale gas motions roiling under Betelgeuse’s red surface are behind the ejection of the massive plume into space.

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