Moon orbiting close to its host planet

  • Thread starter Thread starter willstaruss22
  • Start date Start date
  • Tags Tags
    Moon Planet
AI Thread Summary
A moon can orbit closely to its host planet with limited to no tidal heating if it maintains a perfectly circular orbit and always presents the same face to the planet, resulting in no change in gravitational field and thus no tidal forces. However, if the orbit is eccentric, tidal heating will occur due to the gravitational variations experienced by different parts of the moon. Proximity to the planet affects the period of solar tides, which can produce some heating, but the influence of the planet's tides can be minimal if the orbit is nearly circular. Ultimately, while proximity is a factor, the moon's orbital characteristics and the nature of its gravitational interactions play a more significant role in determining tidal heating. Therefore, a moon can theoretically have limited tidal heating despite being close to its host planet under specific conditions.
willstaruss22
Messages
108
Reaction score
1
Can a moon orbit close to its host planet and have no tidal heating?
Say there is a moon with 0.5 Earth masses and 0.8 Earth radii orbiting a Jupiter mass planet every 18 hours with an eccentricity of 0.00001. There are no moons within 3 million miles of the exomoon in question. Could this moon have limited to no tidal heating or does the proximity of the moon to the host planet guarantee some tidal heating?
 
Last edited:
Astronomy news on Phys.org
hi willstaruss22! :wink:

tidal heating is caused by squeezing and stretching as the moon changes shape

the change of shape is caused by the gravitational force changing on
different parts of the moon

if the moon has a perfectly circular orbit (and the planet has a perfectly circular gravitational field), and if the moon always keeps the same face towards the planet, then there wil be no change in the gravitational field, and no tidal forces or tidal heating

in any other case, there will be :smile:
 
Proximity of the planet is not very relevant. There IS a minimum level of tidal acceleration gradient due to the star. Meaning that the moon will experience solar tides, just like a lone planet would.

There is a small relevance to the proximity of the planet: the distance to the planet dictates the period of solar tides, and therefore their heat production.

The planetary tides can be arbitrarily weak, because the orbit can be arbitrarily close to circle. They, however, can only amplify tides: they cannot in long term cancel the solar tides because they have different period. Solar tides have about two high tides per orbit, tides due to eccentric orbit have one high tide per orbit.
 
This thread is dedicated to the beauty and awesomeness of our Universe. If you feel like it, please share video clips and photos (or nice animations) of space and objects in space in this thread. Your posts, clips and photos may by all means include scientific information; that does not make it less beautiful to me (n.b. the posts must of course comply with the PF guidelines, i.e. regarding science, only mainstream science is allowed, fringe/pseudoscience is not allowed). n.b. I start this...
Asteroid, Data - 1.2% risk of an impact on December 22, 2032. The estimated diameter is 55 m and an impact would likely release an energy of 8 megatons of TNT equivalent, although these numbers have a large uncertainty - it could also be 1 or 100 megatons. Currently the object has level 3 on the Torino scale, the second-highest ever (after Apophis) and only the third object to exceed level 1. Most likely it will miss, and if it hits then most likely it'll hit an ocean and be harmless, but...
Back
Top