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The Icarus Planet


Nyrath

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http://blogs.discovermagazine.com/badastronomy/2009/01/28/weather-sizzles-on-a-planet-that-kisses-its-star/

 

Gas giant HD 80606b orbits the star HD 80606, which is about 190 light years from Earth. Its orbital eccentricity is a jaw-dropping 0.927. This means that the planet starts at a chilly 125 million klicks from it's sun, and over 55 days it plummets to a mere 4 million klicks. The amount of heat it receives from its sun does not double, it does not triple, no, it rises 800 times!!! The planet's atmosphere becomes hot enough to melt copper.

 

The player character's exploration starship establishes a stable orbit around HD 80606b, and starts analyzing the planet. They have more than a month of safety to do their planetary studies. They will be long gone before the temperature rises to dangerous levels.

 

The game master says "Oops, the ship's engine just broke..."

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Re: The Icarus Planet

 

If Ploor is here' date=' that means [b']this[/b] is the Second Galaxy, and it's only a matter of time before Boskone moves in and occupies us!

 

What do you mean? Boskone is already here. They are obviously the ones behind the Trilateral Commission/Bavarian Illumniati/Gnomes of Zurich/Whatever.

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Re: The Icarus Planet

 

Apparently there is a conference going on right now with some results from the COROT satellite. Among these is a transiting exoplanet in a 20-hour orbit -- insanely small -- around a K0V star, and a radius of about 1/8 Jupiter radii, which makes it between 1 and 2 times the size of Earth -- 1.7 earth radii is quoted. Wikipedia, following Sky & Telescope, has the most complete information I've been able to find; this being a conference, it looks like preprints are not yet available. I assume the orbit is circular; the reports available don't have all the technical data.

 

Very small (for an exoplanet), but in that orbit it is not going to be a pleasant place to live. Only about 4 stellar radii from the star, its sun will occupy a large part of its sky on the daylight side.

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Re: The Icarus Planet

 

Very small (for an exoplanet)' date=' but in that orbit it is not going to be a pleasant place to live. Only about 4 stellar radii from the star, its sun will occupy a large part of its sky on the daylight side.[/quote']

Heh. The planet is named "COROT-Exo-7b".

 

So they've finally located the lava planet Excalbia. Instruct the COROT satellite to see if it can spot Abraham Lincoln.

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Re: The Icarus Planet

 

Among these is a transiting exoplanet in a 20-hour orbit -- insanely small -- around a K0V star' date=' and a radius of about 1/8 Jupiter radii, which makes it between 1 and 2 times the size of Earth -- 1.7 earth radii is quoted.[/quote']

It has a 20 hour orbit around its primary?!?!? :eek:

 

I'm sorry, but "insane" just doesn't do justice to that... :ugly:

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  • 7 months later...

Re: The Icarus Planet

 

Followup, inspired by today's APOD image.

 

Houston, we have a rock.

 

The preprint about the CoRoT-7 system is out (has been for almost a month); the press release from ESO has been out for a week. You can get the PDF of the preprint to appear in Astronomy & Astrophysics from that linked page.

 

Two planets in the system, designated b and c. Their masses are 4.8 +/- 0.8 and 8.4 +/- 0.9 Earth masses respectively. Orbital periods are 0.85 and 3.7 days, respectively, with assumed circular orbits of sizes 0.017 and 0.046 AU.

 

They seem to have detected the inner planet, (B), transiting the star. That means, with the spectroscopic orbit solution, we know the size of the planet and therefore its density.

 

b's average density is 5.6 +/- 1.3 g cm^-3. For comparison, Earth's is 5.5 in those units.

 

We got a rock. :celebrate

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  • 3 weeks later...

Re: The Icarus Planet

 

Quick mini-essay on COROT-7b I just threw together

 

With the list of known extrasolar planets getting longer and longer every week, and whole new types of planets like the Hot Jupiters, it's not surprising that we eventually discover an example of something even more extreme - a
named COROT-7b.

 

Cthonian worlds are thought to be what you get when a small gas giant orbits so close to it's parent star that all the 'normal' atmosphere of hydrogen, helium, and lighter gases boils off under the blaze of coronal mass ejections, and the like. In the case of COROT-7b, what we have left is a ball of silicate rock under twice as big as Earth, orbiting so close to it's parent star that the year is
20 hours long
.

 

That's close enough for one side of the planet to fry at 2700 Kelvin ( well over 4000 Fahrenheit ). But because it's so close to it's star - a mere 1.26 million miles - tidal forces have almost certainly locked it - so the dark side would be a mere 288 Kelvin (59 degrees Fahrenheit). Thermochemical equilibrium calculations show that starting with those conditions, and that sort of rock,
- and surprising amounts of oxygen, cracked from the rocks as they boil. Other elements such as magnesium, aluminium, calcium and iron would appear in lesser amounts.

 

But despite the weirdness you'd still get the same kind of weather you get on earth - different layers of atmosphere saturated with different gases, until they start to condense out and fall as rain and hail. But on COROT-7b the oceans are molten lava and the hail is in the form of red-hot pebbles. And they'd fractionate out too, so some storms would rain enstatite and rubies, and others would dump spinel and wollastonite

 

And on top of all that, as the red-hot winds howl around the planet from Hot Side to Dark, the entire daylight atmosphere lights like a sodium lamp, from the sodium metal vapour that makes up most of it reacting to the solar wind from COROT-7.

 

Not a hospitable place - but an
awesome
sci-fi setting.

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