What is Kepler-70b's surface like?

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In summary, Kepler-70b is a very hot, rocky planet that orbits a much brighter star than the sun. It has an escape velocity of 8514 m/s, so any gas less dense than 67g/mol will evaporate over a relatively short timescale. Its equilibrium temperature is about 7770 Kelvins, hotter than the surface of the sun by a substantial margin. The maximum temperature for such a body in the "noon" part of it is 10988 Kelvins.
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Pds3.14
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The hot side of Kepler-70b is immensely hot. It orbits a star 21.8 times brighter than the sun at a distance of just 0.006 AU. The equilibrium temperature of a blackbody at that distance is about 7770 Kelvins, hotter than the surface of the sun by a substantial margin. The maximum temperature for such a body in the "noon" part of it is 10988 Kelvins.

The boiling points at 1 Atmosphere of all known forms of matter are substantially lower than either of these numbers.

And yet, this is classed as a "rocky" planet. Why? Is there something that I'm missing that would allow such a ball of fire to be able to support itself as a ball of rock and not, say, as a ball of lava covered in a multi-thousand-atmosphere glob of metallic vapor?

For that matter, It has an escape velocity of 8514 m/s. If I remember correctly, anything gaseous over 1/5th that speed will escape within a few thousand to a few million years, and the stellar wind will only accelerate that. This means that any gas less dense than 67g/mol, anything with less than a molecular/atomic weight of 67, will evaporate over a relatively short timescale.

This means that CO2, for example, would not be stable in the atmosphere. Worse still, I'm not sure it could even hold together at those temperatures.

So this means that any long-term atmosphere would need to be composed of individual atoms instead of molecules. The lightest individual atom that could be sustained is probably Galium.



Is there something I'm missing that would allow such a planet to exist without being coated in a thick layer of trace metals as gasses?
 
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Pds3.14 said:
And yet, this is classed as a "rocky" planet. Why? Is there something that I'm missing that would allow such a ball of fire to be able to support itself as a ball of rock and not, say, as a ball of lava covered in a multi-thousand-atmosphere glob of metallic vapor?

Kepler-70b is believed to be the rocky core remnant of a gas giant that fell into its star's envelope during its red giant phase. The planet is probably still around in its current form because the star only recently passed through the red giant phase.

http://en.wikipedia.org/wiki/KOI-55
http://en.wikipedia.org/wiki/Kepler-70b
 
  • #3
Drakkith said:
Kepler-70b is believed to be the rocky core remnant of a gas giant that fell into its star's envelope during its red giant phase. The planet is probably still around in its current form because the star only recently passed through the red giant phase.

http://en.wikipedia.org/wiki/KOI-55
http://en.wikipedia.org/wiki/Kepler-70b

Yes, but what IS its current form? A ball of rock? A ball of lava? A ball of compressed metallic vapor? Is it likely to have an atmosphere? Is it evaporating? Is it made of plasma?
 
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I can provide some insight into the surface of Kepler-70b based on the information provided. The extreme heat of the planet's hot side is likely due to its close proximity to its star, which is much brighter than our sun. This results in an equilibrium temperature that is even hotter than the surface of the sun. This intense heat would make it difficult for any known form of matter to exist in a liquid state on the planet's surface.

Despite this, Kepler-70b is still classified as a rocky planet. This is because it is believed to have a solid, rocky surface, even though that surface is incredibly hot. It is possible that the planet's intense heat could cause its surface to be covered in a layer of molten lava, but this would still be considered a rocky surface.

As for the planet's atmosphere, it is likely that any long-term atmosphere would be composed of individual atoms rather than molecules due to the intense heat. This means that lighter elements, such as CO2, would not be able to exist in the atmosphere. Instead, the atmosphere would likely be composed of heavier elements, such as Gallium, which have a higher boiling point and can withstand the extreme temperatures.

In conclusion, while Kepler-70b's surface may seem inhospitable to us, it is still considered a rocky planet due to its solid surface. Its extreme heat and proximity to its star do present challenges for the existence of an atmosphere, but it is possible for heavier elements to exist in a gaseous state and make up the planet's atmosphere. Further research and observations will help us better understand the unique characteristics of this planet.
 

1. What is the surface temperature of Kepler-70b?

The surface temperature of Kepler-70b is estimated to be around 6,800 Kelvin, making it one of the hottest planets discovered so far.

2. Is Kepler-70b a rocky planet?

Yes, Kepler-70b is considered a rocky planet, similar in composition to Mercury in our own solar system.

3. Does Kepler-70b have an atmosphere?

Yes, studies have shown that Kepler-70b does have an atmosphere, but it is very thin and mostly composed of hydrogen and helium.

4. Are there any known moons or rings around Kepler-70b?

As of now, there are no known moons or rings around Kepler-70b. However, further studies may reveal more about its potential satellite system.

5. How does the surface gravity of Kepler-70b compare to Earth's?

Kepler-70b has a much higher surface gravity than Earth, estimated to be around 67 times stronger. This is due to its smaller size and higher density.

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