Does anyone know what the definintion of a Phantom Star is?

Question

its some sort of paranormal or scientific or spiritual (or all) sighting.

Answer 1

I haven't ever heard of it being referred to as a "Phantom Star," but there is a term "Nemesis Star."

This idea arose about 25 years ago and was an afterthought on the same theme of Alvarez's notion of a Planet X.  Both of these were proposed as possible explanations for what were believed to be periodic extinctions of large numbers of species on earth.  Some have challenged that there is any periodicity at all.  It's an emperor's clothes kind of thing.

The Nemesis star was hypothesized to be a very faint red dwarf or brown dwarf star that orbited the sun to a distance of about a thousand times Pluto's orbit.  Out past the Oort cloud, which is a vast but very sparse halo of comets.  Computer simulations showed that if a mass of that size were to come through the Oort cloud on an orbit which brings it closer to the inner solar system, that thousands or even millions of comets could be sent careening in toward the sun.  It was thought that some of these comets might have hit the earth and caused mass extinctions.

Two problems.  This would be a very long term orbit and would only cause this comet rain to occur once every few million years.  Even if millions of comets came into the inner solar system, it is highly unlikely that enough of them would hit the earth to cause widespread extinctions.

The second problem is that the cycle of extinctions just isn't that regular.  

No such star or planet has been detected.  If a Nemesis star exists, we should be able to detect it within the next couple of years, even if it is an extreme distance away.  In any case, it would have to be at least hundreds or thousands of years away from getting close to us, or we would have discovered it by now.

Answer 2

A star that's not visible, or very elusive.