Exploring the Limits of Gas Giant and Terrestrial Worlds

In summary, some physicists are investigating the theoretical limit to how small a gas giant can form, while others are investigating the theoretical limit to the mass of a terrestrial world.
  • #1
natski
267
2
Dear all,

Is anyone aware of any physicists who have worked/working on the theoretical limit to how small a gas giant can form? What is the minimum radius and mass that a gas giant can form at before it's simply evaporates too quickly to become a stable world? I'm guessing some fluid dynamics/planetary formation guys have worked out some kind of rough limit for this?

In contrast, has anyone done the upper limit for the mass of a terrestial world?

Thanks,
Natski
 
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  • #2
The surface gravity compared to thermal velocity should be easy to work out (not having done it myself) how small a gas giant could be.

I don't know if there is a theoretical limit to the size of a rocky planet - it's more the shortage of rock in the inner solar system to form a planet. Again I don't think there are any theories that predict the relative sizes of rocky planets - it's just chance.
 
  • #3
Minimum size for a gas planet is about 3 Earth masses. Maximum size is about 10 Jupiter masses [any larger than that and they self ignite into brown stars]. That is a fairly large range of mass. Rocky planets are less certain. About 10 Earth masses is the practical limit.
 
  • #4
Chronos, can you provide a scientific refernce to the minimum size for gas giants value? I would be interested in seeing a detailed derivation.

I know 10 Earth masses is commonly quoted, but I don't believe there is any real work to substantiate this figure... I would love to read something on it though. I'm thinking of the planetary formation guys...
 
  • #5
The size would depend on distance from the star, type of star (luminosity), and gas composition.

One can compute the escape velocity of hydrogen, since it is the lightest element, as a function of gravity and compared to the temperature distribution of the upper atmosphere. Do the same for ammonia and methane.
 
  • #6
Well yes I could go through the calculation btu I'm sure a much more sophisticated and detailed model ahs been already computed, do you know of a reference?
 
  • #7
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  • #8
natski said:
Well yes I could go through the calculation btu I'm sure a much more sophisticated and detailed model ahs been already computed, do you know of a reference?

Pollack et al. (1996) is the basic paper for our present ideas about the core accretion model. If you buy core accretion (and not core collapse), you might set an (arbitrary) lower limit for what is a giant planet at something that has undergone runaway growth (which is generally considered to occur once a planetesimal hits 10 M_Earth, and is beyond the snow line). The end result will depend on how dense the proto-planetary disk is around your core (i.e. - Jupiter vs. Saturn vs. Neptune/Uranus).
 

1. What are gas giant and terrestrial worlds?

Gas giant and terrestrial worlds are two types of planets found in our solar system. Gas giants, such as Jupiter and Saturn, are large planets made up mostly of gases like hydrogen and helium. Terrestrial worlds, such as Earth and Mars, are smaller, rocky planets with solid surfaces.

2. How do gas giants and terrestrial worlds differ?

Gas giants and terrestrial worlds differ in several ways. Gas giants are much larger and have thick atmospheres, while terrestrial worlds are smaller and have thinner atmospheres. Gas giants also have no solid surface, whereas terrestrial worlds have solid surfaces that can support life. Additionally, gas giants are farther from their host star and have longer orbital periods compared to terrestrial worlds.

3. What is the current research on exploring the limits of gas giant and terrestrial worlds?

Scientists are currently using various methods, such as telescopes and spacecraft, to study and explore the gas giant and terrestrial worlds in our solar system. They are also using computer simulations and data from these missions to better understand the composition, structure, and evolution of these planets. Additionally, there are ongoing efforts to search for exoplanets, including gas giants and terrestrial worlds, in other solar systems.

4. Can gas giant and terrestrial worlds support life?

While gas giants are not conducive to life as we know it due to their hostile environments, some of their moons may have conditions that could potentially support life. On the other hand, terrestrial worlds like Earth have the right conditions for life to thrive. However, further research is needed to determine if there is life on other terrestrial worlds in our solar system or beyond.

5. How does studying gas giant and terrestrial worlds help us understand our own planet?

By studying gas giant and terrestrial worlds, scientists can gain a better understanding of planetary formation and evolution. This knowledge can then be applied to our own planet, providing insights into the origins of Earth and its place in the universe. Additionally, studying these diverse worlds can help us identify potential habitable environments and inform our search for life beyond Earth.

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