Puzzling Six-Exoplanet System With Rhythmic Movement Challenges Theories of How Planets Form (phys.org) 37
Astronomers have used a combination of telescopes to reveal a system consisting of six exoplanets, five of which are locked in a rare rhythm around their central star. "The researchers believe the system could provide important clues about how planets, including those in the Solar System, form and evolve," reports Phys.Org. From the report: The first time the team observed TOI-178, a star some 200 light-years away in the constellation of Sculptor, they thought they had spotted two planets going around it in the same orbit. However, a closer look revealed something entirely different. "Through further observations we realised that there were not two planets orbiting the star at roughly the same distance from it, but rather multiple planets in a very special configuration," says Adrien Leleu from the Universite de Geneve and the University of Bern, Switzerland, who led a new study of the system published in Astronomy & Astrophysics. The new research has revealed that the system boasts six exoplanets and that all but the one closest to the star are locked in a rhythmic dance as they move in their orbits. In other words, they are in resonance. This means that there are patterns that repeat themselves as the planets go around the star, with some planets aligning every few orbits. A similar resonance is observed in the orbits of three of Jupiter's moons: Io, Europa and Ganymede. Io, the closest of the three to Jupiter, completes four full orbits around Jupiter for every orbit that Ganymede, the furthest away, makes, and two full orbits for every orbit Europa makes.
The five outer exoplanets of the TOI-178 system follow a much more complex chain of resonance, one of the longest yet discovered in a system of planets. While the three Jupiter moons are in a 4:2:1 resonance, the five outer planets in the TOI-178 system follow a 18:9:6:4:3 chain: while the second planet from the star (the first in the resonance chain) completes 18 orbits, the third planet from the star (second in the chain) completes 9 orbits, and so on. In fact, the scientists initially only found five planets in the system, but by following this resonant rhythm they calculated where in its orbit an additional planet would be when they next had a window to observe the system.
More than just an orbital curiosity, this dance of resonant planets provides clues about the system's past. "The orbits in this system are very well ordered, which tells us that this system has evolved quite gently since its birth," explains co-author Yann Alibert from the University of Bern. If the system had been significantly disturbed earlier in its life, for example by a giant impact, this fragile configuration of orbits would not have survived.
The five outer exoplanets of the TOI-178 system follow a much more complex chain of resonance, one of the longest yet discovered in a system of planets. While the three Jupiter moons are in a 4:2:1 resonance, the five outer planets in the TOI-178 system follow a 18:9:6:4:3 chain: while the second planet from the star (the first in the resonance chain) completes 18 orbits, the third planet from the star (second in the chain) completes 9 orbits, and so on. In fact, the scientists initially only found five planets in the system, but by following this resonant rhythm they calculated where in its orbit an additional planet would be when they next had a window to observe the system.
More than just an orbital curiosity, this dance of resonant planets provides clues about the system's past. "The orbits in this system are very well ordered, which tells us that this system has evolved quite gently since its birth," explains co-author Yann Alibert from the University of Bern. If the system had been significantly disturbed earlier in its life, for example by a giant impact, this fragile configuration of orbits would not have survived.
Liu Cixin eat your heart out (Score:1)
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Well played.
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"I only barely got my head around the three body problem, and now this?!?"
It's exactly the same it's 2 three-body-problems.
now is the right time... (Score:2)
Aliens (Score:2)
like a Puppeteer's Klemperer Rosette
arXiv preprint to skip the paywall (Score:2)
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Thank you.
My favorite takeaway: "...we show that the amount of gas in the planets does not vary in a monotonous way...".
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I'm just looking at my handy-dandy bucket of astronomical data (a megabyte-plus spreadsheet from many sources) and really failing to see a simple relationship between bulk density and "a" (semi-major axis - broadly equivalent to the orbital potential energy or average distance from the barycentre). There's a vague dip-then-rise but that's pretty
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If in doubt, RTFP.
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The description of a rosette passing by at near-light really got my imagination going, and is one of my favorite little bits.
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Re:Klemperer Rosette (Score:2)
These planets in their Lagrangian resonance chain are very precisely in orbits of differing periods.
I'd have to find and re-read
I'm not worried about the motion (Score:2)
It's the ordering that bothers me. If you assume an accretion disk separates out matter with heavy near the centre, this new system shouldn't exist.
Unless something seriously changed the order in this early state, but I'd have thought that would generally lead to mixing rather than light in the middle.
Something sweeping up heavier elements selectively might do it, but I don't see any way to do that.
There are other planetary formation models, but accretion disk is popular for a reason - and not just for the
Re:I'm not worried about the motion (Score:4, Interesting)
It's the ordering that bothers me. If you assume an accretion disk separates out matter with heavy near the centre, this new system shouldn't exist.
Accretion disk formation is probably quite dynamic. And the dynamics of the matter distribution in the gas cloud could possibly ultimately affect the matter distribution within the accretion disk beyond the standard matter distribution of heavier near the centre.
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I think you've identified where your thinking and reality part company there - just after the "assume" bit.
Yes, there are good reasons to have simple, physics-based models for accretion disks which form by simple processes from simple starting conditions. After all, you can calculate their consequences. That doesn't necessarily mean that the universe has to fol
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Valid for a short time, perhaps, but you're talking 200 million to half a billion years. You also need mass to form clumps. An accretion disk is spun out, it doesn't materialize as a uniform thing.
Now, there was some intersting work on Schrodinger's wave equation modelling such systems very accurately, but as far as I recall that has no application here. It describes the motion in any accretion disk or planetary ring. Perhaps you can give me the DOI.
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Pierson's Puppeteers? (Score:2)
important clues about how planets, including those in the Solar System, form and evolve,"
Evolve?
Maybe some advanced race [wikipedia.org] put them there?
Rythmic movement? (Score:3)
An 18:9:6:4:3 chain? Not very impressed. Call me when they're doing the macarena.
Have we found Jesus? (Score:2)
What's the frequency of the innermost planet? If it's some deep octave of the note G then you have the God Chord: Gsus.
G c g d' d''
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Should have said outermost planet, sorry. The orbital speeds go up toward the star, not away from it.
this reminds me (Score:1)
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From personal observation, no. The oldest person ever reliably recorded died at just over one dozen decades. There are Bronze Age goat-herd stories of people living up to about 8 dozen decades, but these reports are not confirmed by any sources of physical evidence.
Pitching the genuine uncertainties of scientific research in a way suitable to the education of children is very difficult. If nothing else, the time allocation
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I did not know Science wrote school textbooks. I thought Texas did that.
It's just the Puppeteer migration (Score:2)
Just the The Fleet of Worlds moving away from the upcoming core explosion.
Rare? (Score:3)
five of which are locked in a rare rhythm around their central star.
Perhaps not so rare [syfy.com]:
If this one is only 200 light years away, it implies systems like this are common; it seems like long odds one would be so close if they were incredibly rare. Maybe we're the weird system.
Two of the planets are earth-like [esa.int] (in terms of density, I don't know if they are in the goldilocks zone). I wonder what kind of religions the inhabitants on such planets would have, with the to them holy numbers 18:9:6:4:3.
n-body prpblems are hard (Score:3)
and so we will have to throw a few petaflops at this to be able to understand it.
I'll just note (Score:4, Funny)
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If he wanted to calm the astronomers down he should mount outward-facing telescopes on the satellites and give them free access to the data. They wouldn't even have to be that good, the sheer quantity of data from that huge amount of telescopes would make up for it.
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Huh? This required massive telescopes like the VLT, your fake-environmentalist friends are against those too. The whackos you're allying with caused the Thirty Meter Telescope in Hawaii to be paused indefinitely. Space is the only choice left for astronomy. Space-based telescopes are much better suited for this sort of thing anywhere, they can stare at a specific location without being spun around the Earth.
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Huh? This required massive telescopes like the VLT, your fake-environmentalist friends are against those too.
Seriously dude, better check your rageposting. ???I am all about earth bound telescopy, and the people I suspect you are referring to are Hawaiian racists who want to secede and make their own race based country. They hide u8nder a thin veneer of religion, but they want the "Haoles" out of there. Friends? I hope they die out with the rest of the racists.
The whackos you're allying with caused the Thirty Meter Telescope in Hawaii to be paused indefinitely. Space is the only choice left for astronomy. Space-based telescopes are much better suited for this sort of thing anywhere, they can stare at a specific location without being spun around the Earth.
You do have some really serious issues here, when a person posts that earth based telescopes are quite capable, and you go off on some wild 180 degree out o
It was bound to happen (Score:2)
We never thought our inquisitive nature would result in trauma, but now we've found God's sex toy stash.