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View Full Version : Can a Mercury sized moon support an atmosphere?



willstaruss22
2014-Jan-15, 07:45 AM
Lets say there is a gas giant similar to Jupiter orbiting a yellow star similar to our Sun. Around this planet exists a moon with 0.064 Earth masses and 0.4 Earth radii. This would put it into the rocky moon category. The moon orbits at Europa's distance from the planet with a slightly eccentric orbit and the interior would be pushed and pulled by interactions with other moons. Could the tidal heating from the planet cause geological activity on the moon and create an atmosphere in the process?

chornedsnorkack
2014-Jan-15, 08:22 AM
Lets say there is a gas giant similar to Jupiter orbiting a yellow star similar to our Sun. Around this planet exists a moon with 0.064 Earth masses and 0.4 Earth radii. This would put it into the rocky moon category.
Largely irony. But rocky surface, yes.

The moon orbits at Europa's distance from the planet with a slightly eccentric orbit and the interior would be pushed and pulled by interactions with other moons. Could the tidal heating from the planet cause geological activity on the moon and create an atmosphere in the process?
You are not specifying distance from the said sunlike star.
What matters is escape speed.
Titan - 2,64 km/s, massive atmosphere
Io - 2,56 km/s, no atmosphere
Europa - 2,03 km/s, no atmosphere
Ganymede - 2,74 km/s, no atmosphere
Callisto - 2,44 km/s, no atmosphere
Moon - 2,37 km/s, no atmosphere
Mercury - 4,25 km/s, no atmosphere
Mars - 5,03 km/s, thin atmosphere

Your satellite - 4,72 km/s.

willstaruss22
2014-Jan-15, 09:42 AM
The planet and moon would be in the habitable zone of their star and would get 70% the light that Earth gets from the Sun. So it would be like the planet orbiting at a distance in between Mars and Earth. I thought Mars did have an atmosphere.

chornedsnorkack
2014-Jan-15, 09:47 AM
The planet and moon would be in the habitable zone of their star and would get 70% the light that Earth gets from the Sun. So it would be like the planet orbiting at a distance in between Mars and Earth. I thought Mars did have an atmosphere.

Sorry - simple slip of keyboard - thought to say thin atmosphere but wrote standard text.

That satellite is slightly warmer than Mars and also has slightly lower escape speed. Is it enough difference to cause complete loss of atmosphere where Mars holds on to a thin one? Or is it not?

willstaruss22
2014-Jan-15, 09:59 AM
I was thinking of the possibility of an atmosphere because the moon would be geologically active with continuous volcanic activity like Io. However this moon would have a higher escape speed. Mars to my knowledge has very little to no geological activity as of now.