High-resolution images of dying giant star captured

Last Updated: Saturday, August 8, 2009 - 15:42

Washington: An international team of astronomers has made the most high-resolution images of a dying giant star to date.

Led by Keiichi Ohnaka at the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, the astronomers, for the first time showed how the gas is moving in different areas over the surface of a distant star known as Betelgeuse.

This was made possible by combining three 1.8 metre telescopes as an interferometer, giving the astronomers the resolving power of a virtual, gigantic 48-metre telescope.

Using the ESO VLT Interferometer in Chile, they discovered that the gas in the dying star’s atmosphere is vigorously moving up and down, but the size of such “convection cell or bubble” is as large as the star itself.

These colossal bubbles are a key for pushing material out of the star’s atmosphere into space, before the star explodes as a supernova.

Betelgeuse is a so-called red supergiant and approaching the end of its short life of several million years.

Red supergiants shed a large amount of material made of various molecules and dust, which are recycled for the next generation of stars and planets possibly like the Earth.

Betelgeuse is losing material equivalent to the Earth’s mass every year.

“Our AMBER observations mark the sharpest images ever made of Betelgeuse”, said Keiichi Ohnaka at the MPIfR.

“And for the first time, we have spatially resolved the gas motion in the atmosphere of a star other than the Sun. Thus, we could observe how the gas is moving in different areas over the star’s surface,” he added.

The AMBER observations have revealed that the gas in Betelgeuse’s atmosphere is moving vigorously up and down.

The size of these “bubbles” is also gigantic, as large as the supergiant star itself.

While the origin of these bubbles is not yet entirely clear, the AMBER observations have shed new light on the question about how red supergiant stars lose mass: such colossal bubbles can expel the material from the surface of the star into space.

It also means that the material is not spilling out in a quiet, ordered fashion, but is flung out more violently in arcs or clumps.

The death of the gigantic star, which is expected in the next few thousand to hundred thousand years, will be accompanied by cosmic fireworks known as a supernova like the famous SN1987A.

ANI



First Published: Saturday, August 8, 2009 - 15:42

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