Vega has a similar structure to our solar system

Jan 9, 2013 12:21 GMT  ·  By

NASA and ESA have pointed their Spitzer Space Telescope and Herschel Space Observatory at a couple of nearby stars, confirming previous observations and discovering an asteroid belt near the star Vega, the second brightest in the Northern hemisphere.

Astronomers already knew Vega was surrounded by a cool dust cloud, similar to the solar system's Kuiper belt, but have now found a smaller and hotter inner asteroid belt as well, similar to the asteroid belt beyond Mars.

Continuing the parallel with our own solar system, there is a huge gap between the two belts, with the outer belt about 10 times further from its star than the inner one.

Unlike our solar system though, Vega is a big star. It's much younger too, at 400 to 600 million years old. It's twice as large as the sun and burns hotter, making its light bluer.

Likewise, the dust cloud around Vega is about four times larger than the one around the solar system, in fact, the entire solar system would fit comfortably inside the gap around Vega.

There is far more material in both the asteroid and the cool cometary belt of Vega and Fomalhaut than their equivalents in the solar system, both because they are younger, meaning planets haven't had time to sweep up, and because they formed from a larger gas and dust cloud than our solar system.

The space telescopes confirmed the same structure at the same distance ratios around Fomalhaut.

Separately, NASA Hubble scientists provided a much better estimate of the strange orbit of Fomalhaut b, the only exoplanet found around the star which will hit the outer, cooler belt in the next decade or so.

No planets have been discovered around Vega yet, but the large gap between the two belts is a big sign. Astronomers estimate that several Jupiter-sized or smaller planets orbit Vega, creating the clear gap.

The hope is that future telescopes, like the now almost mythical James Webb Space Telescope, will be powerful enough to detect the planets that astronomers believe are there.

Photo Gallery (2 Images)

Artist's impression of the asteroid belt around Vega
Vega and the solar system to scale
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