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back to article Boffins find new way to spot stars which have planets

Astro boffins have developed a simple method for telling which stars have planets and which don't, potentially a great help in hunting for alien civilisations or uninhabited Earthlike worlds ripe for colonisation by humanity*. Artist's conception of a planet orbiting a far-off sun. Credit: ESO Pah - another useless gas giant. …

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Boffin

Looks Simple...

Tidal wash burys the heavier lithium deeper down hence it is not in the outer light emiting layer.

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Boffin

I know why!

Stars without planets are lonely, which over a period of billions of years makes them go bipolar. The lithium stabilizes their moods!

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Boffin

Oh Dear.

Most of the exoplnaets discovered so far have been supermassive 'hot Jupiters', that is gas giants larger than Jupiter which orbit very close to their parent star (e.g. well within the orbit of Mercury). This is because the easiest method of detecting exoplanets is the 'wobble' caused by the orbits of such planets.

Smaller gas planets (such as Neptune) are harder to spot, as are planets orbiting further from their star, as these can only really be spotted when they transit (cross in formt of their parent star), which requires that they orbit in a plane that brings them between us and their parent star.

Small rocky planets, such as Earth are even harder still to spot, with ther discovery requiring methods such as looking for changes in their prent star's emission spectrum when they transit, as their size will mean that they hardly affect the amount of light reaching Earth at all.

Having said all that, what these researchers seem to have found is that there is some sort of relationship between close-orbiting large gas giants and low amounts of lithium in a star. Extrapolating this to draw a parallel between the existence of any sort of planetary system and observable lithium levels in a star's emission spectrum seems to be stretching it a little.

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Thumb Down

What is El Reg coming to?

An entire story about alien worlds and lithium, and you didn't bodge in a single reference to Dilithium crystals? Your standards are slipping!

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FAIL

Some scientists..

“We have now found that the amount of lithium in Sun-like stars depends on whether or not they have planets.”

“There are several ways in which a planet can disturb the internal motions of matter in its host star, [and] thereby rearrange the distribution of the various chemical elements and possibly cause the destruction of lithium. It is now up to the theoreticians to figure out which one is the most likely to happen,”

Without a theory, and experimental proof of said theory, what you have found is called a CORRELATION. Scientists today eh.

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Coat

Safer than electro-convulsive therapy?

So stars without planets are so depressed about it that they have to take lithium supplements?

Mine's the one with the appointment reminder in the pocket.

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Joke

FTL drives obviously

Well clearly on inhabited planetary solar systems the Li2 has been harvested for FTL drives

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Bronze badge

An answer?

It would seem to me that the lithium (and heaver metals) used to make planets are concentrated there rather than in the star. This could be an effect of non-uniform element distribution in progenitor gas/dust cloud if some stellar nurseries collapsed enough for angular momentum to become significant before outlying metals had time to concentrate at the centre, thus being left over for rocky metal-rich planets

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Headmaster

Should that not be

We have now found that the amount of lithium in Sun-like stars depends on whether or not they have very large superjovian planets in a close orbit around them.

But we don't know if that also applies to earth sized plantes in their habitable zone.

Well it's not quite that clear cut is it?

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Happy

Large superjovian planets

This made me think of large superjovial planets, which I guess would be the planetory equivalent of Brian Blessed.

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It's not Lave by any chance?

I blame all those Elite players and their fuel scoops...

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Does this fit with the other Lithium problem?

I wonder if this could be related to their being only 1/3rd as much litium in stars generally as expected refered to recently in a New Scientist article. I think it quite likely that some unknown process in formation of planets & other body from matter which would otherwise be part of the stars is heavily selecting lithium which is thus unobservable. If so one of the few problems with the Big Bang is not a problem.;

"OUR best theories of the early universe also tell us which atoms should have been forged in the first 5 minutes after the big bang. The existing amounts of hydrogen and helium match theory perfectly - so well, in fact, that cosmologists claim this is the best evidence we have for the big bang. Things aren't so good for the third element, lithium, however is different.

When we count up the lithium atoms held in stars, there is only one-third as much of the lithium-7 isotope as there should be. Another isotope, lithium-6, is overabundant: there may be as much as 1000 times too much of it.

So something in the big bang is not adding up."

http://www.newscientist.com/article/mg20327246.700-13-more-things-the-lithium-problem.html

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Maybe

I wonder if there are lithium atoms in the planetary zone that absorb the spectrum emissions of the lithium in the star. Oh, probably not.

As good science goes, this is as if they looked at red, yellow, and blue stars and found that only the yellow ones (hi!) have planets. That doesn't say that there is no blue star in the whole universe with planets, but the other ones are where to look for them.

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Alien

Aliens

Aliens are obviously harvesting lithium from their stars to use it for something. They pick stars with planets because interstellar travel is strictly slower-than-light, so if you're going to set up a mining operation you'd better do it somewhere you can colonize too. Because, by random chance, they evolved sentience a tiny little bit sooner than us, which works out to many millions of years, they've taken up all the good stars in the galaxy already. They haven't bothered to contact us because they don't give a crap and we're screwed anyway.

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Alien

cause and effect?

On most self-respecting planets, the aliens have got lithium battery technology nailed.

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Chicken or Egg?

Is it the presence of planets that disturbs the distribution of lithium in their suns, or is it it just that suns with less lithium are more likely to form planets?

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Joke

Exploding?

"The current exploding smoke-poles will never do in the long run."

Insert pole smoking joke here.

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Boffin

@Ed Blackshaw and Ravinez

@ Ed - It wasnt mentioned in this article, but the actual research paper mentions that our own sun suffers from the same reduction in Lithium as those of the ones measured in the survey.

So whilst one data point is not enough for conclusive evidence it does appear likely that this does apply to a vast majority of star systems not just those with a jovian planet in close proximity... It would be interesting to know whether any of the star systems discovered so far with planets in the similar size range to Earth where measured in this survey...

@ Ravinez - I dont know the specific quantity of Lithium that is "missing", but Lithium is not so hugely abundant in the planets of our solar system that i would imagaine it accounts for all of the missing 99%.

Additionally, if that were the case, you would imagine it would be far easier to find earth like planets orbiting other stars by looking for the drop in percentage of Iron in a Star... considering that a star is mostly made up of light elements, the percentage loss in heavy elements to create a planet would i imagine be a much greater percentage then with Lithium. As that technique hasnt been used i can only guess, the percentage of material lost to form planets is negligible... Still if Iron percentage turns out to be a better way to measure planet bearing stars then i claim first mention here! =P

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