One-Third of Sun-Like Stars May Have Eaten Their Planets (sciencemag.org) 38
sciencehabit shares a report from Science Magazine, written by Adam Mann: Like the Greek god Chronos, a good number of stars devour their children. As many as one-third of them have swallowed one or more of their own planets, a new study suggests. The findings could help astronomers rule out stellar systems unlikely to contain Earth-like worlds. The team investigated how often this happens by looking at 107 binary systems containing two Sun-like stars -- akin to the fictional two-sunned world Tatooine in Star Wars. In 33 of these pairs, one of the companions showed elevated levels of iron compared with the other, a sign of planetary cannibalism. These same partners were also rich in lithium, giving further credence to the world-munching hypothesis. Although Sun-like stars are born with substantial amounts of lithium, they burn it away within the first 100 million years of their lives, so seeing it in the older stars in the study sample indicated it likely came from a planet. Using these different lines of evidence, the team was able to model that between 20% and 35% of Sun-like stars consume a few Earths' worth of their offspring. Such events could happen in systems where gravitational interactions among the planets would either fling one into the central star or bring it close enough for the star to slowly vaporize and devour it. The findings have been published in the journal Nature Astronomy.
Sampling error (Score:5, Informative)
Re: Sampling error (Score:2)
I've read the article and nature abstract (actual paper paywalled), and have the same concern. I feel like that's such an obvious stretch they must address it in the paper, but alas I can't read it.
Applies to Binary Stars only! [Re:Sampling error] (Score:4, Informative)
Exactly!
Showing that binary stars sometimes swallow planets is fascinating, but don't try to extend that statistic to single stars. It tells us nothing about single stars, because three-body systems are chaotic. (Or, more specifically, they contain chaotic regions of the phase space).
For reference, roughly half of sunlike stars are in binary systems.
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But what really matters is how the star identifies itself. What are its pronouns?
The subjective and possessive cases are standard: it / its.
The objective case stars use is non-standard and a bit too long, but I think we should think about adopting it more widely:
GetALifeAlreadyYouFuckingGobshite
You've managed to significantly reduced the average intelligence of all the comments in this post with this one comment. Bravo. That level of idiocy is rare, and we appreciate how graceful you were to self-identify so quickly.
Re: Applies to Binary Stars only! [Re:Sampling err (Score:2)
I'm keeping a close eye on Jupiter.
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"Despite Star Wars, there are no stable orbits in a binary system. "
Damn, you say Earth, Moon and Sun are not 3 bodies? :-)
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Heck, Jupiter practically is a secondary in our own solar system. There are stable orbits in binary systems, orbits that circle both stars, and orbits that circle one are both stable. There are also unstable orbits depending on the orbital distance of the primary and secondary, if they are two close, there are no single star orbits.
To think, sgunhouse got +5 informative with something that Wikipedia can show you is false, is pretty bad.
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OK...so because Jupiter broke up a possible plantoid, there are no stable orbits in the Sol system? I guess we should notify science, an AC says there are no stable orbits in the Sol system...
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Perhaps you should click the "Parent" button a few times. I never commented about the article.
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Lithium depletion requires convection (Score:3)
I thought the lithium argument sounded pretty thin because how does lithium get depleted when it is in the outer layers but googling 'convection lithium star' quickly showed up that low mass stars are supposed to have a stage with a lot of convection.
So the lithium burning stage would have to happen after planets form.
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While stars like the Sun aren't particularly rare, they're also far from common. Only about 1-2% of stars are as massive or more massive than the Sun. The heaviest measured stars are 80-100 time the mass of the Sun (there are some which may be heavier, but in most such cases it is very hard to see through the flying debris to be sure it is one star or two of smaller mass, orbiting
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The number I found (and that is from googling, I am not familiar with the subject) is half the mass our our sun: For that size and lower there is whole body convection burning up the lithium. I didn't realize that covers most of the stars out there.
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And yes, half the Sun's mass being around the half-way point in the IMF sounds about right as well.
I happen to have my handy-dandy notebook of astronomical stuff open, and a 0.5 solar-mass star would have about 6.5% the Sun's luminosity, and a main sequence life time of approaching 80 billion years. My handy-dandy notebook has a boun
Seems Unlikely (Score:5, Interesting)
"Stellar members of binary systems are formed from the same material, and therefore they should be chemically identical."
Isn't this a bit of a leap?
If you start with a single large hydrogen cloud that eventually forms a binary system, the two stars would need to be of a near-identical mass to have the same burn rate - since of course it is stellar gravity that induces fusion. If there is even a small difference in the masses of the two stars, they will burn at different rates, generating different amounts of by-product, which should then be visible in spectrum analysis. They will, of course, start with an identical composition - hydrogen - but burning at different rates would mean they would generate different mixes of heavier elements.
In our solar system, 99.86% of all system mass is contained in our star itself. The four largest outer planets - Jupiter, Saturn, Uranus and Neptune accounting for 99% of the remaining mass. In our system, the four terrestrial planets (Mercury, Venus, Earth and Mars), together with the dwarf planets, moons, asteroids and comets all together compromise less than 0.002% of the solar system's mass [wikipedia.org].
So if the planet nearest our star - Mercury - were to be consumed by Sol... then even accounting for the suggestion that it might take a while to submerge - remember, it is going to be more dense than at least the outermost layers of the sun's surface - and would likely sink towards the core. A planet with a mass less than 0.002% of the sun... It doesn't seem likely that it would leave enough of a trace to be statistically significant. It might appear as a dark spot for a while - at least until the star burned it off...
Whilst it seems reasonable to suggest that measurement of the composition of the star immediately before and immediately after a consumption event might reveal a change, that delta would likely be statistically insignificant compared to the range of composition across different stars.
We'd never know if it had happened or not.
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Re: Seems Unlikely (Score:1)
And there's a decent chance that a ninth planet was ejected.
There's also a slightly less-than-decent chance that it was blown up. ;)
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But while the star is on the main sequence (i.e. for the kinds of stars that would be described as "sunlike") the only important fusion processe
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You're not being any kind of pain by pointing out that the authors and reviewers of the piece could run [planetary] rings around me.
I'm still fascinated by the idea that the absorption of a planet by a star could yield an alteration in the star's absorption spectra that we could detect - given my earlier observation regarding the (in)significance of the mass of Mercury to sol. And given, of course, that Sol is a relatively small star in the grand scheme of things.
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There have been several such events reported in the astronomical literature over the last few decades. I think at least one of them was an offshoot of Kepler observations of a star with irregular dimming, and follow-up as an o
And so (Score:2)
1/3 of binary stars with unstable planetary orbits are like this. Ergo one fifth to one third of normal stars are because a planet might fling anothe
I like astronomy (Score:2)
You can randomly postulate a theory. Everybody will discuss it, and nobody can disprove it. It is a win-win.
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That's not how science works. Let's find the definition of science in a way that you will appreciate:
* You mean a hypothesis.
* And then, still, it's only a hypothesis, if it makes testable predictions.
* Which this paper does, as far as I can tell.
* And even then, those predictions need to be actually verified by observation, to even be able to dare calling it a theory.
* Though technically, there is no such thing as proof, as the best you can ever get is statistically reliable observation. A single conflicti
Surprisingly few. (Score:2)
If you ever played with those simulations with the random objects affected by gravity, you know that the likeliness of a long-term stable rotation is extremely small, almost negligible.
It definitely takes several things to be juust right, to get everything in the system to be stable from the start, to achieve that..
The most impressive thing is that there are planets at all.
Titan, not god (Score:3)
Chronos was a Titan, father of the gods, not a Greek god himself.
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Chronos was a Titan, father of the gods, not a Greek god himself.
I know that Chronos wasn't an insufferable know-it-all who was nitpicking other people's statements, just to show how smart he is.
Best headline ever (Score:2)
Sol star hungry! Sol star eat planets!
PLAAAANET!!! (Score:1)
Fake news! (Score:2)
That's ridiculous! Suns don't eat pla~`^% &m [NO CARRIER]
"Children"? (Score:2)
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