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Gliese 876 's Terrestrial Size Planet; Perhaps another Venus.
Topic Started: Jun 14 2005, 05:45 AM (94 Views)
somerled
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Admiral MacDonald RN
Earth-like EXTRA SOLAR planet detected About time - At last !
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Earth's bigger, hotter planetary cousin may have been detected orbiting a star in our cosmic neighbourhood, astronomers said.

The most Earth-like of all 155 so-called extrasolar planets found orbiting stars besides our sun, the newly unveiled planet is probably rocky like Earth, rather than big and gassy like Jupiter and most other extrasolar planets discovered in the past decade, the scientists said at a briefing.

"It took 150 observations of this star to glean the existence of this Earth-like planet," said planet hunter Geoffrey Marcy of the University of California, Berkeley. "This will definitely be one of our favourite stars from now on."

"It's a very unearthly world," said Jack Lissauer of NASA's Ames Research Center. "It's likely to be the first rocky planet orbiting a star like our sun."

"It's like Earth's bigger cousin," Paul Butler of the Carnegie Institution of Washington said in a statement accompanying the announcement. Butler is a member of the team that found the planet.

The new planet is the smallest extrasolar planet ever detected, with about 7.5 times the Earth's mass. Before this, the smallest planets found orbiting stars besides the sun were at least 15 times Earth's mass, making them more like distant, icy Neptune.

Too hot

By contrast, this planet's surface is far too hot - ranging from 204 degrees to 371 degrees Celsius - to support life as it is known on Earth.

While Earth orbits the sun at a distance of about 150 million kilometres, this extrasolar planet almost hugs its star, orbiting about 3.2 million kilometres from the star Gliese 876 in the constellation Aquarius, just 15 light-years from Earth.

A light-year is about 10 trillion kilometres, the distance light travels in a year. In astronomical terms, 15 light-years is right around the corner.

The new planet races around its star once every two Earth days or so, and has a radius about twice the size of Earth, the astronomers said. The star it orbits is about one-third Earth's mass.

Like dozens of other extrasolar planets detected over the past 10 years, this one was first discovered by the distinctive wobble its gravity exerts on the star it orbits. As it happened, this is the third planet circling that particular little star.

The two others are gas giants like Jupiter and orbit much farther out.

Astronomers have no direct proof the new planet is a space rock like Earth, but its low mass means it probably is not a giant gas planet like Jupiter, the scientists said.

Planet hunters have detected three other rocky planets outside our solar system, but all three orbit a pulsar - the remnant of an exploded star - so this is the only planet orbiting a normal star.

A team of scientists has known about the new planet for three years but wanted to confirm its theory it was a terrestrial planet before going public, Marcy said.


More info
Quote:
 
The newly-discovered “super-Earth” orbits the star Gliese 876, located just 15 light years away in the direction of the constellation Aquarius. This star also possesses two larger, Jupiter-size planets. The new planet whips around the star in a mere two days, and is so close to the star's surface that its temperature probably tops 400 to 750 degrees Fahrenheit (200 to 400 degrees Celsius)—oven-like temperatures far too hot for life as we know it.

and
Quote:
 
The team measures a minimum mass for the planet of 5.9 Earth masses, orbiting Gliese 876 with a period of 1.94 days at a distance of 0.021 astronomical units (AU), or 2 million miles.


Gliese 876 (a local red dwarf)
Posted Image
Gliese 876

Detaiils of Gliese 876 solar system (as discovered so far)
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Swidden
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Adm. Gadfly-at-large; Provisional wRench-fly at large
I think this is just the beginning of terrestrial type planets being discovered over the next decade or so. From the items I've read about plans and projects in development for furthering these searches, I wonder if it will be too long before we have the hints of worlds that might be "potentially" habitable...
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somerled
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Admiral MacDonald RN
Swidden
Jun 15 2005, 12:01 AM
I think this is just the beginning of terrestrial type planets being discovered over the next decade or so. From the items I've read about plans and projects in development for furthering these searches, I wonder if it will be too long before we have the hints of worlds that might be "potentially" habitable...

This one is not likely to be habitable , it would be a hellish place , if it has an atmosphere.
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