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Planet Found With Comet-like Tail
Nat Geo ^ | July 15, 2010

Posted on 07/21/2010 5:56:31 AM PDT by NYer

A so-called cometary planet is shown in an artist's rendering.

HD 209458b, shown in red in an artist's conception, is the first confirmed "cometary planet," experts say.

Image courtesy G. Bacon, NASA/ESA

An alien planet orbits so close to its star that its atmosphere is being blasted away, forming a gaseous, comet-like tail, astronomers announced Thursday.

(Related: "Odd Star Sheds Comet-like Tail.")

About 153 light-years from Earth, planet HD 209458b hugs its star so tightly that the planet's atmosphere is likely a scorching 2,000 degrees Fahrenheit (1,093 degrees Celsius) an a year passes in just 3.5 days—making Mercury's 88-day orbit seem downright leisurely.

That tight orbit also means this gas giant—meaning it's made primarily of gas—is subjected to blistering forces from its host star, which scientists say are the cause of HD 209458b's comet-like tail.

"This planet is getting blasted by the star and that's blowing the atmosphere off," said astronomer Cynthia Froning of the University of Colorado, who was involved in the study of the comet-like planet.

(Also see "Star 'Eating' Superhot Planet's Atmosphere.")

Comet-like Tail Streaming Toward Earth

HD 209458b is one of the few known transiting planets—planets that appear to periodically cross the faces of their host stars, as seen from Earth.

This means light from HD 209458b's star must pass through the planet's atmosphere before reaching us.

By studying the filtered starlight, astronomers can determine such a planet's atmospheric composition and also the direction and velocity that any gas lost to space is moving.

Using the Hubble Space Telescope's Cosmic Origins Spectrograph, astronomers recently detected evidence of a tapered gas tail streaming away from HD 209458b and toward Earth at a speed of about 22,000 miles an hour (35,400 kilometers an hour).

Comet-Like Planet to Disappear?

The most likely explanation for the comet-like feature is that the star's solar wind—actually a stream of charged particles—is evaporating the gas giant a bit at a time, astronomers say.

HD 209458b is losing about 80,000 pounds (36,000 kilograms) of mass a day—or about a billionth of Earth's mass every year, according to the new research.

Given enough time, the comet-like planet could theoretically evaporate away completely, but it would take about a trillion years. "That's longer than the life of the star," Froning said.

It's unclear how long the superheated alien world's "tail" is or how long it's been losing mass, but it's almost certain the erosion process has been happening for at least several million years, she added.

(Related: "New 'Impossible' Planet May Be on a Death Spiral.")

Comet-like Planets Common?

While its been speculated that stars can blast away planets' masses, HD 209458b is the "first confirmation" that atmospheric stripping is a real phenomenon, said study leader Jeff Linsky, also of the University of Colorado.

And since HD 209458b is a pretty typical "hot Jupiter"—the nickname for close-orbiting gas giants—it's "almost certain" that all hot Jupiters have comet-like tails, Linsky said.

"I think they're all going to be losing mass, and they're all inevitably going to have tails," he added.

The comet-like planet research is detailed in the July 10 issue of Astrophysical Journal.

TOPICS: Culture/Society; Miscellaneous; News/Current Events
KEYWORDS: astronomy; astrophysics; catastrophism; hd209458b; universe; velikovsky; xplanets

1 posted on 07/21/2010 5:56:36 AM PDT by NYer
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To: sig226


2 posted on 07/21/2010 5:57:31 AM PDT by NYer ("God dwells in our midst, in the Blessed Sacrament of the altar." St. Maximilian Kolbe)
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To: NYer; All

Planet algore?

3 posted on 07/21/2010 6:16:09 AM PDT by TMSuchman (John 15;13 & Exodus 21:22-25)
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To: NYer

Can’t contemplate about something that large now, everything is racial politics. It trumps everything. Space exploration/study is for an advanced society, not ours.

4 posted on 07/21/2010 6:22:43 AM PDT by central_va (I won't be reconstructed, and I do not give a damn.)
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To: central_va

It is interesting, is it not, how Progressivism retards a civilization in the name of advancing it?

5 posted on 07/21/2010 6:28:20 AM PDT by andy58-in-nh (America does not need to be organized: it needs to be liberated.)
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To: TMSuchman
Image and video hosting by TinyPic
6 posted on 07/21/2010 6:29:47 AM PDT by cripplecreek (Remember the River Raisin! (look it up))
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To: NYer

That is the result of the Industrial Revolution on that planet, too many SUV’s and not enough govmint subsidies for green energy.

7 posted on 07/21/2010 6:42:06 AM PDT by VRW Conspirator (George W. Bush was the last conservative democrat)
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To: NYer

We never saw that planet on Star Trek!

8 posted on 07/21/2010 8:22:54 AM PDT by Sarajevo (You're jealous because the voices only talk to me.)
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To: Sarajevo

Because it’s not a Class-M planet. You couldn’t have landing parties investigating hot, gas giants (like Jupiter).

9 posted on 07/21/2010 4:42:27 PM PDT by fieldmarshaldj (~"This is what happens when you find a stranger in the Amber Lamps !"~~)
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To: 75thOVI; aimhigh; Alice in Wonderland; AndrewC; aragorn; aristotleman; Avoiding_Sulla; BBell; ...
An earlier topic, and a related archival topic: Thanks NYer.
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10 posted on 07/26/2010 8:12:45 PM PDT by SunkenCiv ("Fools learn from experience. I prefer to learn from the experience of others." -- Otto von Bismarck)
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To: NYer


11 posted on 07/26/2010 8:14:02 PM PDT by dragnet2
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To: KevinDavis; annie laurie; Knitting A Conundrum; Viking2002; Ernest_at_the_Beach; Mmogamer; ...
Note: this topic is from 7/21/2010. Thanks NYer. Sorry I didn't ping this then.
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Google news searches: exoplanet · exosolar · extrasolar ·

12 posted on 10/27/2013 6:13:02 AM PDT by SunkenCiv (
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To: SunkenCiv

13 posted on 10/27/2013 6:17:28 AM PDT by JoeProBono (SOME IMAGES MAY BE DISTURBING VIEWER DISCRETION IS ADVISED;-{)
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