Discovery of an extrasolar earth-sized planet

Oct 08, 2010
An artist's conception of the extrasolar planetary system around the star Kepler-9. Astronomers have discovered an earth-sized planet in this system. Credit: NASA, Kepler, T. Pyle

(PhysOrg.com) -- There are now over 490 confirmed extrasolar planets. The vast majority are gas giants like Jupiter, but they are much stranger because many orbit close to their stars and so are much hotter than Jupiter (some are even closer to their star than Mercury is to the sun).

The new data are revolutionary for astronomers trying to understand how the solar system and its planets developed, with hundreds of examples to analyze now instead of just one (our own). As search techniques are further improved and refined, scientists are on the look out for earth-like planets: those with about the same mass and size as the Earth, and located at a distance from their star where water is liquid (the so-called "" since is essential to life as far as we know).

The spacecraft was launched in March of 2009 to study extrasolar planets. One of its major goals is the detection of terrestrial planets in habitable zones. Since launch, it has been staring at over 150,000 stars, looking for the telltale brightness dips that suggest a planet has passed across the face of the star (a transit), thereby blocking some starlight from reaching Earth. Of course there are many other effects that can temporarily dim a star's light, for example. Moreover, modeling of the planet's properties (mass, orbital radius) is complicated by the presence of multiple planets, and when there is one planet there are likely to be others. So far, however, the efforts at detection and modeling have been fruitful, although neither the Kepler team nor any other has reported finding an earth-like planet.

The quest for other earths is making good progress, however. Writing in the latest issue of the journal Science, a team of twelve CfA astronomers led by Matt Holman, together with a large group of colleagues, report using Kepler to discover an earth-sized extrasolar planet. They carefully analyzed the orbital motions of two Saturn-sized extrasolar planets in the system known as Kepler-9, and found that by meticulously accounting for their motions they could subtract their effects to hunt for even smaller dips, as small as 0.02% in stellar intensity.

They report finding a planet whose size is only about 1.5 earth-radii, making it one of the smallest known. This planet orbits the star (its "year") in only 1.5924 days, however, and so it is very close to its star, hot, and thoroughly unearth-like. Nevertheless it represents a major step forward in the search for small planets. Unlike other recent discoveries (like that of a planet in its habitable, "Goldilocks," zone but considerably larger than the Earth), this new planet is small enough to raise expectations and the excitement for soon discovering extrasolar earths.

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User comments : 9

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Megadeth312
5 / 5 (2) Oct 08, 2010
Gliese 581g
Quantum_Conundrum
3.5 / 5 (4) Oct 08, 2010
Well, Gliese 581g would almost certainly be a better place to live than the hell hole known as Kepler 9.
yyz
5 / 5 (6) Oct 08, 2010
It would seem that this planet is too hot to retain any real semblance of an atmosphere but future discoveries of Earth-sized exoplanets with substantial atmospheres are surely out there. This is important in that by transiting their parent stars, spectroscopic analysis of their atmospheres should be possible (though very difficult). So the hunt continues for exo-Earths with atmospheres, but its just a matter of time.

An early draft of the Science paper: http://arxiv.org/...93v2.pdf

Up-to-date wiki-page on the system: http://en.wikiped.../KOI-377

BTW, Kepler-9 (aka KOI-377) is 650pc away.
eurekalogic
5 / 5 (3) Oct 09, 2010
Now if we could just get there to study these solar systems.
stanfrax
1.5 / 5 (2) Oct 09, 2010
yeah great another dream planet - hang on a min - wait - im on one - its perfect for life
SteveL
5 / 5 (3) Oct 09, 2010
yeah great another dream planet - hang on a min - wait - im on one - its perfect for life


But, if only it had intelligent life.
kevinrtrs
1.7 / 5 (6) Oct 11, 2010
The new data are revolutionary for astronomers trying to understand how the solar system and its planets developed, with hundreds of examples to analyze now instead of just one (our own)


Definitely a time to get rid of the accretion model.

If been falsified at every nook and turn and yet the evolutionists still cling doggedly to the outmoded, archaic piece of irrationality.
This simply because everything is supposed to have made itself.

Hot Jupiters absolutely and totally defies the accretion model but do you hear the scientists decry it? No. It remains a sacred cow to be hallowed by everyone.
The solar system, like the rest of the universe was created by an intelligent and highly creative mind. So creative that every planet, star and galaxy will be found to be unique.

rbrtwjohnson
not rated yet Oct 11, 2010
Even more, it is exciting the discoveries of new Earth-sized exoplanets. I believe mankind needs to develop more efficient spacedrives to take us to these new worlds in our lifetime.
http://www.youtub...AHXN_kAY
Skeptic_Heretic
3 / 5 (2) Oct 12, 2010
Hot Jupiters absolutely and totally defies the accretion model but do you hear the scientists decry it?
Because they don't deny the accretion model. Evidence your stance.
The solar system, like the rest of the universe was created by an intelligent and highly creative mind. So creative that every planet, star and galaxy will be found to be unique.
And 99.999999999% completely unsuitable for your life. Perhaps your creator thinks that you shouldn't leave your little cage. How benevolent of him.

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