The Sun lacks lithium because it has planets… sounds more like an affect, not a cause.
When making a claim, you have to be able to differentiate between the two, and solve for both.

Also, the sample isn't completely random and it is imbalanced as well. You can't take 500 stars, and stick in the values of 70, which are known… against others which are unknown. This is basically akin to "slight of hand". It is very likely many of the Stars which are currently assumed to have no planets, actually do.
Basically, I wouldn't buy this paper as an undergrad thesis.

“The explanation of this 60 year-long puzzle is for us rather simple,” said Garik Israelian, lead author on a paper appearing in this week's edition of Nature. “The Sun lacks lithium because it has planets.”

Um, describing a correlation constitutes an "explanation"? Baloney.

So now we know how the Ganaeans did it.

[Obscure reference to A.E. van Vogt's "Resurrection" - actually the Ganaeans claimed their technique to localize suns with planets was "unique and coincidental".

Also, look at the populations in the paper, they overlap. Its not useful for individual stars.]

This is one of the interesting cases where correlation is a strong contender with causation. Causation is the parsimonious case. (E.g. with correlation you have to add an object and a process compared to causation.) But as there are many more possibilities for correlations they can win out. (E.g. biology, with its many contingencies.)

I'll bet on causation though, there are many possible mechanisms as well here.

Btw, thanks for the link to the paper, Nancy!

It an interesting corrolation, assuming it's not coincidence.

From the paper:

"We performed different two-sample statistical tests using ASURV (version 1.2). All tests consistently confirm (at the 3? level) that the planet-host and single star populations are not drawn from the same parent population. [Ref. removed.]"

So if it was just an ad hoc observation it would be too close to a coincidence to be useful, you would like at least 5 sigma separation. But as there is a set of likely hypotheses around (see above) that it is testing, it's sound.

LC

It an interesting corrolation, assuming it's not coincidence.

(L/L') ~ MR^2*freq/mr^2*freq'

= (M/m)(R/r)^2*(freq/freq').

So the ratio of masses M/m ~ 1000, the ratio of solar radius to Jupiter's orbital radius is R/r ~ 1/1000, and the frequency ratio is about ~ 144. So we put it into the ratio of angular momenta amd L/L' ~ .14 . If I restore the 2/5 for the momentu of intertia of a solid sphere I get the angular momentum of Jupiter is about 17 times that of the sun.

LC

At the formation of the solar system, heavier elements probably made their way to the centre of the system, while lighter elements tended to drift outwards where they could have been trapped by the dust clouds that became planets.

This might be tested by comparing lithium concentrations of planets relative to their distance from the sun. If the theory holds, you would expect Mercury to have very little lithium, and Neptune to have a much higher concentration than closer planets.

It is curious that planet producing stellar systems would have little lithium in the star. It is in line with the question of why comets have different concentrations of deuterium than Earth does.

LC