Saturday 31 January 2009



SEPTEMBER 03, 2013 - SPACE - There's a "blue marble" alien planet just 63 light-years from Earth, but the world is anything but friendly to life. Researchers say the blue color in the atmosphere likely comes from a rain of molten glass.

This illustration shows HD 189733b, a huge gas giant that orbits very close to its host star HD 189733. The planet's

atmosphere is scorching with a temperature of over 1000 degrees Celsius, and it rains glass, sideways, in

howling 7000 kilometer-per-hour winds. Image released July 11, 2013.

This super-hot glass rain is just one consequence of the close proximity between the gas giant alien planet HD189733b and its sun. which causes daytime temperatures to soar as high as 1,700 degrees Fahrenheit, scientists said.

A fresh set of observations of the planet in X-rays also suggest HD189733b has an outer atmosphere that is far larger than expected.

These surprise finds are all signals that so-called hot Jupiter alien planets are worthy of study on their own, even though they are hostile planets to life, researchers said.

Rewriting planetary formation


Hot Jupiters are large, roughly Jupiter-sized planets that become very hot by circling tight around their stars. These worlds have been described as planetary daredevils because they orbit so close to their parent stars that they risk being consumed. Often, one side of the planet is tidally locked to the star, exposing that side to scorching hot temperatures, while leaving the other side permanently turned away.

This illustration shows a "hot Jupiter" planet known as HD 189733b orbiting its star, HD 189733. The NASA/ESA

Hubble Space Telescope measured the actual visible light color of the planet, which is deep blue.

Image released July 11, 2013.

A giant blue planet is found, but the color could be due to glass particles in the hellish planet's

hot atmosphere. See how it was found in this SPACE.com infographic.

Hot Jupiters are easy to spot from a distance because as they pass in front of a star, their disc blots out a large portion of the star's light; HD189733b causes a three per cent drop in its star's light, for example. The planets' gravitational pull often causes their parent stars to wobble, too.

While common in the universe, however, Hot Jupiters are totally different than what denizens of Earth's solar system encounter. In our case, small, rocky planets orbit close to the star and the gas giants are much farther out.

The latest observations of HD189733b are challenging some theories of planetary formation and are just one of the reasons Hot Jupiters are earning more attention from astronomers these days.

"At first considered to be the 'chaff' researchers would have to wade through to get to the fainter Earth-like worlds, hot Jupiters are now attracting their own attention," NASA scientists wrote in a recent Science@NASA post about these planets.

Boiling atmosphere


This plot compares the colors of solar system planets to the color of the hot Jupiter HD 189733b. With the

exception of Mars, the colors are primarily determined by the chemistry of the planets' atmospheres.

Image released July 11, 2013.

This illustration shows a "hot Jupiter" planet known as HD 189733b orbiting its star, HD 189733. The NASA/ESA

Hubble Space Telescope measured the actual visible light color of the planet, which is deep blue.

Image released July 11, 2013.

New attention came to HD189733b, which was discovered in 2005, after two X-ray observatories watched the blue planet pass across the face of its star. Both NASA's Chandra X-Ray Observatory and ESA's XMM Newton saw a drop in X-rays from the star that was three times more than that observed in optical light.

This means the planetary atmosphere is much larger than previously thought. It's also bleeding quickly. HD189733b's atmosphere is fleeing the planet at a rate of 220 million pounds to 1.3 billion pounds a second, a new study estimated.

"The extended atmosphere of this planet makes it a bigger target for high-energy radiation from its star, so more evaporation occurs," Scott Wolk, an astronomer at the Harvard-Smithsonian Center for Astrophysics, said in a statement.

A wide field image of the region of sky in which HD 189733b is located. In this image we can see the asterism

of the "Summer Triangle" a giant triangle in the sky composed of the three bright stars Vega (top left), Altair

(lower middle) and Deneb (far left). HD 189733b is orbiting a star very close to the center of the triangle.

Image released Dec. 11, 2007.

A star field image showing the star HD 189733 (center). The NASA/ESA Hubble Space Telescope has given astronomers

a fascinating new insight into the atmosphere of HD 189733b. To the right of the star is the notable planetary nebula

Messier 27. Image released Dec. 11, 2007.

HD189733b could also have bright planet-wide auroras due to the extensive stellar radiation hitting it, but that's speculation at this point, the study authors said.

The study has been accepted for publication in the Astrophysical Journal, and is available now on the prepublishing site Arxiv. - FOX NEWS.


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