You can wonder if, in absence of an atmosphere, like mercury, whether it would have a tail, and THAT would be a similar one to that from pluto.

We don’t have to wonder whether Mercury has a tail, because such a tail has been observed. Mercury is known to have an intrinsic magnetic field.. This field is only about 1% of the strength of Earth’s magnetic field, so distance and time scales of the solar wind’s interaction with Mercury are considerably shorter than for Earth, but the physics is otherwise the same. Material from the sunward side of Mercury is ablated and photoionized into an ionosphere (as opposed to being dissociated and then photoionized at Earth), and these ions (Na+ being the most abundant, because sodium is relatively common and has a very low first ionization potential) are detectable downtail, in the same way we see O+ from Earth’s ionosphere downtail. The chemistry may be different, but the physics is the same.

Venus does not have an intrinsic magnetic field, so the physics of how the solar wind interacts with it has important differences. The entire dayside atmosphere is exposed to the solar wind, not just the cusp and polar cap regions like at Earth and Mercury. The interaction is similar to what we see at comets, the main difference being that Venus has a much stronger gravitational field and therefore loses proportionately less material.

The unknown with Pluto is whether it has an intrinsic magnetic field or not. If yes, then the interaction will be similar to Mercury’s, where an ionosphere that has formed due to ablation from the surface contributes to a magnetically confined tail. If not, then Venus is your model for the interaction. Again, it’s not necessarily the same chemistry, but it is the same physics. The solar wind doesn’t care whether the ion it picks up was already in the atmosphere or freshly ablated from the surface.

No, it’s got one in the same way the moon has one. There are molecules in gas form trapped by the planet, but it’s not one thick enough to have a thermodynamic temperature, because it’s far too rare.

So if it was a gas before it got hit by the solar wind, it can’t have been volatile.

And no, they aren’t being ejected because they are volatile.

We have an atmosphere, pluto doesn’t. One is the result of sublimation, the other from the force of thermal motion of the gas BEFORE IT LEAVES THE PLANET.

They aren’t the same thing, eric. They aren’t the same thing.

The tail pluto shows has a different source from that of venus.

You can wonder if, in absence of an atmosphere, like mercury, whether it would have a tail, and THAT would be a similar one to that from pluto.

But the one you’re talking of is from a different mechanism.

Are you sure you mean a tail, or are you confusing the stripping of the atmosphere of Venus with a tail created from evanescent material *and particles* in a cometary tail?

These two things are the same physical process. As long as the material is volatile, it’s a detail whether the picked-up ion was already a gaseous neutral atom/molecule or something that was ablated from a solid surface before it was photoionized. Either way, the particles are confined to a plasma tail by the surrounding solar wind.

http://apod.nasa.gov/apod/ap160101.html

Note the potential differences in the angles between the two tails… Depends on where they are in their orbits.

Pluto DOES have an atmosphere, although rather tenuous, and subject to change (sublimation & freezing on the surface) as its orbit takes it further from the Sun.

Pluto doesn’t have an atmosphere, and not because the sun’s so close it’s blowing off the atoms.

http://apod.nasa.gov/apod/ap160429.html