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Old 09-02-2012, 01:29 AM
 
Location: Wasilla, Alaska
17,825 posts, read 20,504,794 times
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Quote:
Originally Posted by NightBazaar View Post
Great info, thanks! Do you have a link for that? I'd like to Bookmark it.
Actually, that information came from the link you provided in post #3.

The nature of the Kepler-47 system - Charlotte Mathematical Science | Examiner.com

Quote:
Originally Posted by NightBazaar View Post
Well, yes, in the end it would cook. The thing about Io is that it experiences Tidal Heating in part (a large part) because of the pull of Jupiter's gravity. But it's also tugged from the other side by the gravitational pull of Europa. Io is closest to Jupiter and Europa is second. Both Jupiter and Europa sort of keep Io in its orbit, but not without causing significant effects to Io. The result is that Io ends up being tidally stretched like a piece of taffy, the effect of which causes extreme friction inside Io, which in turn causes Io's interior to heat up and eject material in the form of volcanoes. So, yes, it would heat up from Tidal Heating, but I think it would probably fragment before actually entering Jupiter.

I would think if there was a reduction in the orbits of both Io and Europa, Io would probably begin to break up. Once the chunks drift close enough to Jupiter and fall into the atmosphere, they'd definitely heat up and cook the remains. A similar example of celestial bodies is Shoemaker-Levy which began breaking up from a very close pass near Jupiter in 1992 on its way toward the sun. That breakup was clearly the result of Jupiter's gravity. It appears the fragments exploded after entering Jupiter's upper cloud layer in 1993

Tidal Heating Tutorial

Tides and Volcanoes on Io: Tidal Forces Cause Volcanic activity on Jupiter's Moon Io | Suite101.com

Comet Shoemaker-Levy 9
I was aware of the tidal forces being exerted against Io by both Europa and Jupiter, but as you mentioned, that requires very specific conditions to be met. I was thinking of the Io Plasma Torus, which produces approximately two trillion watts of electrical power. The current follows the magnetic field lines to Jupiter's surface where it creates lightning in the upper atmosphere.

Considering Kepler-47c is 17 times the mass of Jupiter, and less than half of Jupiter's size, I would imagine either more moons than Jupiter, or larger moons, or possibly both.
Kepler-47c would also be generating its own internal heat as a result of deuterium fusion and may have its own "moon" habitable zone.

Kepler-47 is certainly more than a binary system, but since brown dwarfs are not considered stars, it is something less than a trinary system. Brown dwarfs are also not considered planets. They fall into the category of failed stars.

Last edited by Glitch; 09-02-2012 at 01:43 AM..
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Old 09-02-2012, 02:27 AM
 
5,206 posts, read 8,210,851 times
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Quote:
Originally Posted by Glitch View Post
Actually, that information came from the link you provided in post #3.

The nature of the Kepler-47 system - Charlotte Mathematical Science | Examiner.com



I was aware of the tidal forces being exerted against Io by both Europa and Jupiter, but as you mentioned, that requires very specific conditions to be met. I was thinking of the Io Plasma Torus, which produces approximately two trillion watts of electrical power. The current follows the magnetic field lines to Jupiter's surface where it creates lightning in the upper atmosphere.

Considering Kepler-47c is 17 times the mass of Jupiter, and less than half of Jupiter's size, I would imagine either more moons than Jupiter, or larger moons, or possibly both. Kepler-47c would also be generating its own internal heat and may have its own "moon" habitable zone.

Kepler-47 is certainly more than a binary system, but since brown dwarfs are not considered stars, it is something less than a trinary system. Brown dwarfs are also not considered planets. They fall into the category of failed stars.
Shows how much I remember. I posted that link primarily because of the illustration showing the diagram of the system.

It'd be interesting to know where the information came from. There are a lot of links explaining various terms, but no reference as to where Matthew Reece got the info. Apart from what he describes, I haven't heard anything indicating that the planet is a brown dwarf, only that it's probably a gas planet. It might be that it is a brown dwarf, but that may be jumping the gun a bit. The planet itself hasn't been directly seen to know exactly what it is, unless there's more detailed information than has been released about it. Both planets were detected by the transit method by examining the light curve a star when an exoplanet passes in front of the star.
Methods of detecting extrasolar planets - Wikipedia, the free encyclopedia


Here's what NASA has to say about both planets.
NASA - NASA's Kepler Discovers Multiple Planets Orbiting a Pair of Stars


Here's what NASA's Kepler page has to say about them. It doesn't say much more either, except to say that the possibility can't be ruled out that there might be a chance the planet "could have a large moon with a solid surface and liquid water lakes or seas." Maybe, but I don't think there's any way of knowing right now.
Kepler-47: Our First Binary Star 2-Planet System
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Old 09-02-2012, 10:24 AM
 
Location: Wasilla, Alaska
17,825 posts, read 20,504,794 times
Reputation: 6500
Quote:
Originally Posted by NightBazaar View Post
Shows how much I remember. I posted that link primarily because of the illustration showing the diagram of the system.

It'd be interesting to know where the information came from. There are a lot of links explaining various terms, but no reference as to where Matthew Reece got the info. Apart from what he describes, I haven't heard anything indicating that the planet is a brown dwarf, only that it's probably a gas planet. It might be that it is a brown dwarf, but that may be jumping the gun a bit. The planet itself hasn't been directly seen to know exactly what it is, unless there's more detailed information than has been released about it. Both planets were detected by the transit method by examining the light curve a star when an exoplanet passes in front of the star.
Methods of detecting extrasolar planets - Wikipedia, the free encyclopedia


Here's what NASA has to say about both planets.
NASA - NASA's Kepler Discovers Multiple Planets Orbiting a Pair of Stars


Here's what NASA's Kepler page has to say about them. It doesn't say much more either, except to say that the possibility can't be ruled out that there might be a chance the planet "could have a large moon with a solid surface and liquid water lakes or seas." Maybe, but I don't think there's any way of knowing right now.
Kepler-47: Our First Binary Star 2-Planet System
Mathew Reece got his information from NASA. See Kepler Discoveries

Kepler-47b, at only 2.7 Jupiter masses and only 0.265 times the size of Jupiter, is too small to be a brown dwarf. However, Kepler-47c, at up to 17 Jupiter masses and only 0.410 times the size of Jupiter, certainly falls into the brown dwarf category. Brown dwarfs need to be at least 13 Jupiter masses in order to fuse deuterium. Objects below 13 Jupiter masses are sometimes referred to as "sub-brown dwarfs."

The original scientific paper on Kepler-47 can be found at: Kepler-47: A Transiting Circumbinary Multiplanet System

Unfortunately, I do not possess a subscription to the American Association for the Advancement of Science (AAAS).
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Old 09-02-2012, 01:09 PM
 
5,206 posts, read 8,210,851 times
Reputation: 3188
Quote:
Originally Posted by Glitch View Post
Mathew Reece got his information from NASA. See Kepler Discoveries

Kepler-47b, at only 2.7 Jupiter masses and only 0.265 times the size of Jupiter, is too small to be a brown dwarf. However, Kepler-47c, at up to 17 Jupiter masses and only 0.410 times the size of Jupiter, certainly falls into the brown dwarf category. Brown dwarfs need to be at least 13 Jupiter masses in order to fuse deuterium. Objects below 13 Jupiter masses are sometimes referred to as "sub-brown dwarfs."

The original scientific paper on Kepler-47 can be found at: Kepler-47: A Transiting Circumbinary Multiplanet System

Unfortunately, I do not possess a subscription to the American Association for the Advancement of Science (AAAS).
Thanks for the links Glitch. That's a big help. Seems like Reece could've added a link to his article, unless he did but I missed it.

I hear what you're saying about brown dwarf stars, but I'm not so certain it applies to Kepler-47c. The International Astronomical Union makes the following statement:

Since both planets are rather small, they do not gravitationally disturb the stars or each other measurably. Hence their masses cannot be directly measured. However, astronomers can place upper limits to their masses, showing that these small objects are certainly planets and not brown dwarfs.


However, the IAU also offers this interesting statement (assuming there are any large moons):

While the outer planet is probably a gas giant planet and thus not suitable for life, large moons, if present, would be interesting worlds to investigate as they could potentially harbour life,says William Welsh (San Diego State University, USA), co-author of the study.

Kepler Discovers Planetary System Orbiting Two Suns | Press Releases | IAU
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