I Planetary Orbits in AU - Stability & Mass Limits

[QuantumPowered]

All of the planets should have individual orbits, and should be between the mass of Mercury and Mars. What can their orbits be in AU's? Is there a way to find out how close they can be without destabilizing each other? If we assume the star is about the same size as Sol.

 

[davenn]

All of the planets should have individual orbits, and should be between the mass of Mercury and Mars. What can their orbits be in AU's? Is there a way to find out how close they can be without destabilizing each other? If we assume the star is about the same size as Sol.

have a look at our own solar system as an example. Considering that the habitable zone is relatively narrow, I would suggest that it's likely to be only one, with maybe the possibility of 2 planets sharing the same orbit but on opposite sides of the orbit ( and I'm not really sure that that scenario can exist ?)D

 

[QuantumPowered]

I think it is likely to be more than one, if we assume the habitable zone stretches from 0.7 AU to 1.5 AU.

 

[davenn]

I think it is likely to be more than one, if we assume the habitable zone stretches from 0.7 AU to 1.5 AU.

you miss the point

you wouldn't get 2 planets orbiting within that narrow zone and still have stable orbits
not going to happen, there would be too much gravitational interaction between the 2

 

[QuantumPowered]

No I'm not "missing the point", it is possible to get two or more planets in that zone. Venus orbits at 0.72 AU, Earth at 1.00 AU, and Mars at 1.52 AU. It should be possible to have multiple lower mass planets orbiting at similar distances from 0.7 AU to 1.5 AU, orbital resonances could stabilize such a system.

 

[davenn]

but Venus is far from being habitable
and Mars isn't much better

 

[QuantumPowered]

Mars is believed to have lost most of its atmosphere because of the lack of a magnetic field, and also asteroid impacts. With a thicker atmosphere and a magnetic field Mars would be habitable. The temperatures on Venus aren't caused by the closer distance to the sun, it is entirely related to the atmosphere, also the slow rotation leading to no magnetic field. A planet with a thinner atmosphere, magnetic field and a limited water reserve would be habitable at that distance.

 

[tony873004]

Here are 2 online calculators that compute the interior and exterior reach of a planet around a star. Objects within this reach will not be stable.

Use n = 3 for circular orbits. Plugging in Earth's values shows that Earth destabalizes the region from 0.95 to 1.05 AU.

http://orbitsimulator.com/formulas/reachinterior.html
http://orbitsimulator.com/formulas/reachexterior.html

 

[berkeman]

Welcome to the PF.

No I'm not "missing the point", it is possible to get two or more planets in that zone.

Such an assertion requires a reference to a peer-reviewed publication about it. That's in the PF rules. Can you please provide such a link?

You started this thread with a question, which is fine. But turning around and making assertions requires valid references.