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First signs of extrasolar water

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First signs of extrasolar water
dimka
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Posted 04/11/07 - 07:45 AM:
Subject: First signs of extrasolar water
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New Scientist is reporting an impressive discovery:

First sign of water found on an alien world

Water has been detected in the atmosphere of an alien world for the first time, a new analysis of Hubble Space Telescope data suggests. Water was widely believed to exist on the planet, but previous observations with other telescopes had failed to find it.

The planet, called HD 209458b, is about 70% as massive as Jupiter and is scorched by the heat of its parent star, which it orbits 9 times as close as Mercury does to the Sun.

Because it is one of a small number of extrasolar planets observed to pass directly in front of and behind their parent stars as seen from Earth, astronomers have been able to glean a lot of information – such as its size and mass – about the distant world.

In February, researchers using the infrared-sensitive Spitzer Space Telescope announced that there was no sign of water vapour in its atmosphere. Since the molecule is expected to be abundant in the atmospheres of extrasolar planets, some speculated that the water signal was obscured by a dusty haze.

Now, Hubble observations seem to have revealed the missing water. Travis Barman of Lowell Observatory in Flagstaff, Arizona, US, did a computer analysis of previously obtained Hubble data taken when the planet partially eclipsed its parent star.
Filtered starlight

The amount of light blocked during these eclipses was previously used to precisely determine the planet's radius, which is about 30% greater than that of Jupiter.

Hubble observed light from the host star that had filtered through the outer reaches of the planet's atmosphere. Because of its specific chemical composition, the atmosphere is more transparent at some wavelengths than others.

Barman found clues to this composition by making different models of the atmosphere, each with a different chemical makeup, and seeing which fit the observations best.
Inhospitable world

He says the relatively small amount of light filtering through at about 0.9 microns suggests the presence of water, which absorbs light at this wavelength.

"To me, that's a clear indication that water is there," Barman told New Scientist. "I think this is the first time we've had strong evidence that there's water in at least one extrasolar planet."

But despite the presence of water, he points out that the planet's prevailing temperatures of about 1000° Celsius mean conditions would not be favourable to life. "It's not a place you or I would want to visit," he says.
Uniform temperature

Mark Swain, a member of one of the Spitzer teams that found no evidence of water and a scientist at NASA's Jet Propulsion Laboratory, says the new result may shed light on the planet's temperature.

In order for Spitzer to detect water molecules by they way they absorb light, the planet's interior has to be hotter than its upper atmosphere.

If the planet has a relatively uniform temperature throughout, however, that – and not the obscuration by dusty clouds – could explain the lack of a water detection by Spitzer.

"It's certainly an interesting result," he told New Scientist. "These planets have been surprising us all along."

What do you guys think? Maybe there are other civilizations and other intelligent life forms outside of our solar system after all smiling face
perseus
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Posted 04/15/07 - 09:47 AM:
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Water is probably quite abundant in the Universe. It is a stable molecule composed of two common elements, hydrogen and oxygen so this comes as no great surprise. Consider the moons of the outer planets of our solar system and comets, these contain a great deal of water ice. There is nothing to think that our solar system is particularly special except perhaps the stability and spacing of the planets orbits so it would be quite a mystery to find a lack of water in other solar systems. I doubt if it increases the chance of finding life very much relative to what we previously expected. Now if they could detect a non natural molecule, that would be something really special.

The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man. George Bernard Shaw
Kronocide
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Posted 04/17/07 - 03:27 PM:
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Can you detect organic molecules from spectral analysis? I guess it would have to exist in extreme quantities...

...it is a burnt sacrifice, an offering made by fire, of a sweet savour unto the LORD. --LEV. 1:17
perseus
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Posted 04/25/07 - 01:32 PM:
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http://news.bbc.co.uk/1/hi/sci/tech/6589157.stm

This one looks more interesting, since it is an Earth sized planet with a rocky surface at about the correct temperature and in interstellar tems quite near (20LY) near enough to study.

The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man. George Bernard Shaw
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