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Do Red-Dwarfs eat Rock.s ? Do red-dwarf stars tend to draw in , and ingest , their close-in rocky planets ? The answer , surprisingly , appears to be yes ! The mechanisms for such a draw-down appear to be both tidal- gravitational ,and magnetic in nature . They mainly affect the closer in bodies , but since they are all tidally conjoined and synchronized , lowering one orbit lowers them all ( slowly ). It is stellar rotation that does the job. If is fast ( Trappist1 ) then the stellar influence upholds the inner planet's orbits , while allowing further out planets to descend into resonant orbits with them . If the stellar rotation is slow ( Proxima , Ross 128 ) , then the magnetic and tidal drag spirals the close-in planets into the red-dwarf , leaving only further out rocky worlds . It is suggested here that a standard be established for the likelihood of planets around red-dwarf stars. Such should include stellar mass , rotation period , and age , as well as lithium presence . OK , dwarf stars get hungry ! P.M.
The nearest examples of this effect are Luna ( rising tidal ) , and Phobos ( lowering tidal ) .
Try Neptune's moon Triton . At 1700 miles diameter it not broken .
I contrast red-dwarfs with yellow dwarfs because , as you realized , yellow dwarfs lift their satellites to higher orbit ( Earth ~1Mkm. , while red-dwarfs draw theirs in . The nearest examples of this effect are Luna ( rising tidal ) , and Phobos
Quote from: Professor Mega-Mind on 19/09/2018 11:46:11I contrast red-dwarfs with yellow dwarfs because , as you realized , yellow dwarfs lift their satellites to higher orbit ( Earth ~1Mkm. , while red-dwarfs draw theirs in . The nearest examples of this effect are Luna ( rising tidal ) , and Phobos The reason that our Moon rises away from the Earth whereas Phobos falls towards Mars is due to the transfer of tidal energy. The Earth spins faster than the Moon orbits around it, so the Moon can gain energy through tidal interactions with the Earth. In the process, the Earth's rotation slows down. The opposite is true of Phobos because it orbits Mars faster than Mars rotates. Neptune's satellite Triton orbits the planet in the opposite direction of its spin, which means that tidal forces slow down both Triton's orbit (drawing it in closer) and slow Neptune's rotational speed as well.
Both rotation & revolution can last forever , in theory , but in reality ; friction & other energy transfers modify these characteristics severely over time .
A yellow-dwarf planet can surely migrate inwards..
Let's try to focus on evidences (For real Moons and Planets).1.Rise away:Do you agree that all planets in the solar system rise away from the Sun while all real moons rise away from their host planets?
2. Rotational speedDo you agree that all planets and moons in the solar system slow down their rotational speed over time?
It seems to me that objects can't keep their current orbital radius forever. They must rise away or draw in closer over time.Kepler formula is Ok for very limited time frame.However, the time effect is missing in that formula.
Do you agree that due to this time effect, all real moons and planet must rise away?
If that is correct, then "Tidal" might not be the correct answer for our discussion.
The clinching evidence for this effect is the relative dearth of close-in planets around slower-spinning stellar bodies .
If you are questing for planets within 5 million miles of their parent bodies , you will find a paucity of these around yellow-dwarf stars , let alone white/blue stars
Quote from: Dave Lev on 19/09/2018 16:31:23Let's try to focus on evidences (For real Moons and Planets).1.Rise away:Do you agree that all planets in the solar system rise away from the Sun while all real moons rise away from their host planets?No, I don't. As has already been pointed out, Triton and Phobos are both slowly spiraling in towards their host planets. They are "real" moons and I don't know what dictionary definition of "moon" you would be using to disqualify them as such.
Quote from: Dave Lev on 19/09/2018 16:31:232. Rotational speedDo you agree that all planets and moons in the solar system slow down their rotational speed over time?Without any external forces at work, yes, they would. However, tidal forces have the potential to speed them up under the right circumstances. Such should be happening with the Mars-Phobos system right now.
Quote from: Dave Lev on 19/09/2018 16:31:23It seems to me that objects can't keep their current orbital radius forever. They must rise away or draw in closer over time.Kepler formula is Ok for very limited time frame.However, the time effect is missing in that formula.Correct. Orbits change over long periods.
Quote from: Dave Lev on 19/09/2018 16:31:23Do you agree that due to this time effect, all real moons and planet must rise away?No. They can only rise away if there is some source of energy they can exploit that allows them to enter a higher state of potential energy (i.e. a higher orbit). Tidal forces are one such source, although solar wind and radiation pressure might also contribute a very small amount.
Quote from: Dave Lev on 19/09/2018 16:31:23If that is correct, then "Tidal" might not be the correct answer for our discussion.Tidal effects are not the only thing that affects orbits. Gravitational radiation causes planets and satellites to lose energy over time and for their orbits to decay. The Moon is rising away from us at the moment, but will eventually stop and begin moving back in once gravitational radiation becomes the dominant force at work (barring that the Sun is likely to destroy the Earth and Moon long before that happens, of course). However, orbital decay due to gravitational radiation it is an extremely slow process that is easily overwhelmed in the short term by other factors on the scale of mere planets.
It is stated clearly and we can also see that Triton and Phobos are irregular objects.Any moon or planet which has an irregular shape, must be considered as a broken object.This broken object could be an indication that in the past it had been collide with other object.The impact due to collision could set into orbital decay. But this inwards direction is not due to gravitational radiation. So, in this discussion we only focus on moons and planets with regular shape (None broken objects - I call them REAL moons and planets.)Therefore, do you agree that as Triton and Phobos do not have a regular shape, they can't give any indication for any other none broken object (Noon or planet)?
Currently, we have only tested two none broken objects. Earth and Moon.We have found that both of them are rising outwards.We also assume that all the other planets in the solar system are rising outwards.So, do you agree that from statistical point of view, 100% of the tested none broken objects are drifting outwards?
If that is correct, than it is solid evidence that any none broken objects (Moon, planet and even stars) must rise outwards.
If we want to believe that due to tidal or any other idea, none broken object can rise inwards - we must offer a real evidence for that.
Without it, do you agree that the idea of rising inwards for none broken objects is only a speculation?
You are using nice words as: Tidal, Solar wind, Radiation pressure... but so far we didn't find even one real evidence to support this hypothesis.
Why do we believe that the Moon will eventually stop and begin moving back?Do you agree that it is a pure speculation?Can we offer even one evidence for that (based on none broken moon)?