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KIC 8462852[1] (unofficially called WTF) (Read 16655 times)
Bob
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KIC 8462852[1] (unofficially called WTF)
10/17/15 at 03:45:26
 
Has anyone got a sim of this one yet? I would think that for those dips, we would need to look at Trojans, and a hell of a lot of them.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #1 - 10/17/15 at 12:13:40
 
Quote from Bob on 10/17/15 at 03:45:26:
Has anyone got a sim of this one yet? I would think that for those dips, we would need to look at Trojans, and a hell of a lot of them.

I was thinking the same thing.  The dips in the light curve are not symmetrical like you would expect for a round planet.  And a planet would have to be have to be star-size to create the observed dips.  That can't happen.
 
A swarm of objects might do the trick.  The problem is that swarms tend to spread out.  Perhaps Trojan is the solution to that problem.  But a trojan swarm should produce periodicity.  Stuff that orbits, including trojan swarms, has an orbital period.  The dips in the light curve don't do so periodically like you would expect.  Even if the people suggesting "alien" are correct, solar panels around a Dyson sphere should have orbital periods and a periodic dimming would be expected.
 
Perhaps if the trojan swarm had a high inclination with respect to their parent object, their longitude of ascending node might be shifting so quickly that their plane moves into and out of the plane required to observe them from Earth.  I'll try to set up a simulation of this later.  If you can think of any other reason a swarm of orbiting objects would not show periodicity, let me know and we'll try that too!
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #2 - 10/17/15 at 23:59:19
 
Hi Tony,
 
We do seem to have a dip at about 780 days and another at about twice that. Frankly I don't like the idea of some sort of cometary shooting match at about Mars' orbit. That might sole the infra red problem but the odds of our just happening to see it are very small. Now, someone on facebook posted an animated gif of Trojans that looked like a Wankel Engine. Greeks leading, Trojans lagging but with a third smaller group (Myrmidons?) at the mid point. The gif was looking straight down on the Trojans but we know that in 3d it's going to be more complicated. Some Greeks are defecting to the Trojan camp, and some Trojans are defecting to the Myrmidons, then Myrmidons to the Greeks.
 
If the whole thing precesses, and we have a mixed bag of albedos, then that may account for the star's variations.
 
Then of course we don't know a great deal about that nearby dwarf star, other than it's "now" at about 800 a.u. First thin though is to see if we can construct a solar system with large numbers of Trojans at around Mars' orbit that have remained fairly stable for a few billion years.      
 
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #3 - 10/18/15 at 00:17:38
 
As a little aside, someone was talking; about a fortnight ago, in a facebook group; about an old Nasa plan, to place three satellites at the Earth's Trojan points. The object b being, to try and detect gravitational waves. Because of budget cuts the project was given to ESA. Costs had gone up because of the discovery of an Earth leading Trojan.
 
That's a sobering thought, if this project is our start on a minuscule Dyson structure, and we have the remotest possibility of someone, "only" 1500 light years away, in the process of building a "Ring World", then the buggers know that the Earth is here. They may well have listened to us but sadly the Synod of Whitby, didn't broadcast in vhf  Smiley That distance fits with the Drake equation, and would mean that these guys are going to be about sixteen thousand years ahead of us.  
 
I'm working on making a huge white flag  cry  Sad
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #4 - 10/18/15 at 00:23:38
 
Quote from Bob on 10/17/15 at 23:59:19:
Now, someone on facebook posted an animated gif of Trojans that looked like a Wankel Engine. Greeks leading, Trojans lagging but with a third smaller group (Myrmidons?) at the mid point. The gif was looking straight down on the Trojans but we know that in 3d it's going to be more complicated. Some Greeks are defecting to the Trojan camp, and some Trojans are defecting to the Myrmidons, then Myrmidons to the Greeks.

At the midpoint sits the planet.  So this wouldn't work.  Trojans can't simply trade camp.  I'd love to see the gif.  Do you have a link to the facebook page?
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #5 - 10/18/15 at 01:31:56
 
Try this, you have to scroll way down the thread to find it. The talk about was about Hilda objects.
 
https://www.facebook.com/groups/telescopeaddicts/
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #6 - 10/18/15 at 01:43:39
 
Trojans pure sang indeed do not change camp , lets say by "definition" . But coorbitals can .
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #7 - 10/18/15 at 01:57:33
 
Scroll  down to see this post  
 
 
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #8 - 10/18/15 at 04:29:59
 
Here in this forum there is some info about the dynamics of the Hilda family .  
http://www.orbitsimulator.com/cgi-bin/yabb/YaBB.pl?num=1363161503/2#2
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #9 - 10/18/15 at 06:56:33
 
Hi Bob ,  
Searching for this star I see a lot of blablabla articles about alien megastructures , but it's hard to find the actual data.  
Can you post a valid source showing the data ?
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #10 - 10/18/15 at 09:54:30
 
The wiki page gives basic data
https://en.wikipedia.org/wiki/KIC_8462852
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #11 - 10/18/15 at 10:11:23
 
Quote from frankuitaalst on 10/18/15 at 06:56:33:
Hi Bob ,
Searching for this star I see a lot of blablabla articles about alien megastructures , but it's hard to find the actual data.
Can you post a valid source showing the data ?  

 
Hi Frankuitaalst,
 
This is the article about the discovery, currently the most reliable and complete source:
 
- http://arxiv.org/pdf/1509.03622v1.pdf
 
 
 
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The diversity of the phenomena of nature is so great,and the treasures hidden in the heavens so rich,precisely in order that the human mind shall never be lacking in fresh nourishment.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #12 - 10/18/15 at 10:51:15
 
Thanks for the link to the paper . First link seems to be the good one !
As far as I read the light curves don't fit with a periodic  planetary system orbiting the star , at least not in a transiting orbit.  
Orbiting debris chunks may perhaps be an explanation , but I don't understand how a debris system can create such large dips (20% ) down .
I first thought about a Kuiper belt object (our KB ) transiting the star by accident , for the first big dip  , but I guess this should create a much shorter signature ...  
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #13 - 10/18/15 at 12:31:41
 
I just made 2 Hildas simulations.  They're at the bottom of the Simulations page: http://orbitsimulator.com/gravitySimulatorCloud/simulations/
 
They're the same simulation but from different vantage points.
 
The first is a typical top-down view showing 400 Hildas orbiting the Sun in a rotating frame that holds Jupiter stationary.
 
In the 2nd simulation, the rotating frame is turned off and the vantage is changed to a distant observer in the plane of the Hildas.  You can see the 3 "camps" causing dips in the light curve followed by the thin areas.
Unlike the WTF star, these dips are still periodic.
 
Here's a new guess.  Perhaps a binary planet orbits this star, and one of the members has a huge ring system like J1407B.  Being part of a binary might explain the lack of peroidicity.  As the barycenter of the binary orbits the star in a periodic fashion, the actual planet with the rings may or may not be in perfect alignment to cause a light dip.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #14 - 10/19/15 at 02:37:11
 
Hi Tony,
 
From the "Where's the flux" paper, it doesn't look as though a super Saturn is involved. I haven't had a chance to digest it fully yet but they did look at the light contribution from the close by dwarf star. I would have thought that a super Saturn, with seemingly, its pole flipped towards us, so it rolls around its orbit like Uranus, would reflect a lot of WTF's light back from the rings.
 
At the moment my money is on a large diameter bunch of asteroids close in, i.e. at about 3 a.u. Rather than a smaller diameter, further out, 20 a.u. grouping.
 
Early day though.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #15 - 10/19/15 at 09:20:00
 
A quick couple of questions, the Hildas, seem to interact with only about a quarter of the Trojans, what happens when one collides with a Trojan? A rare event but not as rare as a comet hitting a Trojan.
 
2: Can a Hilda, object swap with a Trojan?
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #16 - 10/20/15 at 02:47:28
 
It looks like the Hildas can run asymmetrically.  
Try this one  
ln(3.793667894) / ln(2)
So that 1.333333333333 / 0.69314718 = 1.923593388
2^1.923593388
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #17 - 10/20/15 at 23:34:13
 
This one from this board looks good. Note that "breathing" effect, I think that is somehow controlled by the Hildas. http://www.orbitsimulator.com/yabbfiles/Attachments/GravSim_JupiterTrojans_1Jup_ Rev.gif
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #18 - 10/21/15 at 12:56:09
 
Quote:
A quick couple of questions, the Hildas, seem to interact with only about a quarter of the Trojans, what happens when one collides with a Trojan? A rare event but not as rare as a comet hitting a Trojan.
2: Can a Hilda, object swap with a Trojan?

In the simulations, they can't interact.  The Hildas and Trojans are massless particles.  In the real solar system they are not massive enough to have appreciable gravity, so they don't interact either.  I doubt they can swap since their semi-major axes are totally different.
 
Quote:
It looks like the Hildas can run asymmetrically.  
Try this one  
ln(3.793667894) / ln(2)
So that 1.333333333333 / 0.69314718 = 1.923593388
2^1.923593388

I'm not quite sure what you're doing here?
 
Quote:
This one from this board looks good. Note that "breathing" effect, I think that is somehow controlled by the Hildas. http://www.orbitsimulator.com/yabbfiles/Attachments/GravSim_JupiterTrojans_1Jup_ Rev.gif

There are no Hildas in the simulation that made this animation.  Even if there were, they would be massless and unable to affect anything.
The "breathing" effect is from Jupiter's eccentricity.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #19 - 10/27/15 at 03:52:07
 
What I get is that because of orbital velocity changes on one leg of our sixty degree triangle, we get more asteroids at one Trojan point than the other two.That's down to changes in orbital velocity due to Jupiter being at aphelion or perihelion. But that cycles, and at times we can have the leading Trojan point having more or less than the other two. We see an asymmetry of the light dips.
 
  Well, that's all well and good but we have to swap the numbers. There are very few Hildas v Trojans. We have about a million 1km diameter Trojans, and only about 1200 Hildas. A set up with about 75% Hildas is going to be reasonably stable but why do two solar systems arrange asteroids so differently?
 
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #20 - 10/31/15 at 00:31:14
 
One possibility , without having analysed the full paper content ,  if we assume the trojan scenario , is that the first dip at 800 days may be due to giant planet transit . The irregular dips at around 1550 days may be due to a trojan swarm transit either leading or trailing . This means 750 days between the trojans and the giant planet ( 60°) . This means a period for the planet of about 6*750 days = ca. 4500 days .
Assuming the mass of the star having 1.43 solar mass ( wiki ) , we get an SMA for the planet of 6 AU.
Orbital period and SMA are same order as our Jupiter  .  
If the hypothesis is correct the light curve should show dips  around about 50 days ( a few are there)  
Edit the following sentence is incorrect: or at 1550+750=2300 ( no data available ) .  
.  
I don't know if the trojans can have enough mass (or surface) to explain the rather serious dips.  
 
Edit : checking the transit time of the hypothetical planet which would cause the dip in the light curve at ca. 800 days , assuming it being at 6AU gives a transit time of about 1.3 days . This might correspond to the dip in the light curve at ca. 800 days , which seems to be in the order of 1.5-2 days .
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« Last Edit: 11/01/15 at 01:07:11 by frankuitaalst »  
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #21 - 10/31/15 at 23:36:36
 
I commented on this guy's blog, and he seems to think that we would need a lot more Jupiter Trojans than our solar system has. The stuff on KIC is the third blog.
 
http://aleph.se/andart2/
 
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #22 - 11/01/15 at 03:30:34
 
Yes , a lot more trojans than in our solar system , is one possibility .  
Another possibility are coorbitals.
It may be possible that the supposed gas giant has some coorbital planets in the same orbit . Such a system has a lot of dynamical behaviour .
I remember once having simulated our Earth having up to five or six companions in the same orbit .  
AFAIR the system was stable in SMA , but showed a lot of dynamics , meaning planets moving towards each other in their orbit quite close .
Maybe Tony joins in here to express his experience ..
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #23 - 11/01/15 at 08:31:48
 
Yeah, the planet that is supposed to have hit the proto-Earth may have been a co-orbital.  
 
Edited;- But we still have that huge 22% dip. So if we up the percentage of Hildas, then we are going to have low velocity collisions around the Lagrange points. So maybe push the sum mass up to something like the Moon's mass, and have a natural log curve for the collision debris. I think we need to be thinking in terms of surface area, of masses from a km in diameter down to metres in diameter. As they are low velocity collisions, we're not going to get a lot of dust.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #24 - 11/01/15 at 11:21:23
 
To illustrate the dynamical behaviour of possible coorbitals :  
hereby an animation I created some years ago , of 6 Earth planets originally positioned at 60° in our solar system  
After a while the system gets excited  ie chaotical in Mean Anomaly , but preserving the SMA to the central star .  
Such a system resembles a trojan system , but with the difference  the notion of L4 and L5 points becomes irrelevant , because every coorbital may in fact be found  outside the L4 and L5 points.  
 
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0_60_120_180_240_300_Earths_Anim_5000y_.gif
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #25 - 11/01/15 at 17:42:00
 
Quote:
he seems to think that we would need a lot more Jupiter Trojans than our solar system has

It would have to have more Trojans than Jupiter.  We discovered Jupiter's trojans with telescopes, not by noticing large patches of star fields disappearing from our skies.  Otherwise, the ancient civilizations would have discovered Jupiter's trojans.
 
The problem with trojans is that they should have periodic motion.
 
Also, if there were so many trojans that they could noticeably block light, there would be lots of collisions between them.  They would grind themselves so fine that the stellar wind would blow them away.
 
Quote:
It may be possible that the supposed gas giant has some coorbital planets in the same orbit . Such a system has a lot of dynamical behaviour .

This dynamically behavior is only evident in a rotating frame over long periods of time.  We aren't viewing this star in a rotating frame.
 
I mentioned earlier about a super-Saturn.  I didn't read the paper.  Have they ruled this out based on IR or for other reasons?  To an outside observer, Saturn would cause the greatest light dip on the Sun.  It's also the only thing that would cause a non-symmetric dip, as it is not spherical.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #26 - 11/02/15 at 02:31:17
 
Won't it work rather like a pair of tinted glasses? I've got a pair of tinted glasses, which are barely tinted, looking out of them there's next to no change in light, but seen from twenty metres away, people see the tint. Here we're talking about a few A.U's but now the people are standing 1400 light years away.  
 
Neptune has ten times as many 1km diameter Trojans as Jupiter, that's the estimate according to Wiki.  Their density suggests that they are basically dirty ice. Their relative velocities are so low that they can just stick together. It might well be that dumbbell comets come from that swarm. But back to Jupiter's Trojans and Hildas, they knock chunks off each other over four billion years but do they grind each other to dust? Mightn't it be the case that very small fragments, from collisions, build up slightly larger fragments over time? So that we have building and demolition going on constantly.
 
We could just wait and see what SETI says; they say a paper will be out in about a month or so, but it would be a laugh to pip them to the post.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #27 - 11/02/15 at 03:20:33
 
Quote from Bob on 11/02/15 at 02:31:17:
Neptune has ten times as many 1km diameter Trojans as Jupiter, that's the estimate according to Wiki.  Their density suggests that they are basically dirty ice. Their relative velocities are so low that they can just stick together. It might well be that dumbbell comets come from that swarm. But back to Jupiter's Trojans and Hildas, they knock chunks off each other over four billion years but do they grind each other to dust? Mightn't it be the case that very small fragments, from collisions, build up slightly larger fragments over time? So that we have building and demolition going on constantly.
.
I'm not sure either if the trojan population of Jupiter is yet built up into bigger bodies or is grinded up to smaller bodies.
I've no reference I'm aware of . Personnaly I guess both processes are going on , both building and also grinding .  
I can imagine fi. that in case two trojans collide in a frontal collision their mutual velocity is reduced to zero and under good cirumstances the resulting debris stays in the neighbourhood and gradually is reabsorbed by the new trojan , resulting in a trojan having more or less the mass of both parental trojans.  Other scenarios however are also easily to imagine.  
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #28 - 11/02/15 at 23:04:29
 
frankuitaalst, do your co-orbital planets start out as that? We have just a lot of dust which needs to form into a planet. So does it do that, then migrate; with several others into the co-orbital configuration?  
 
I've never been a great fan of the idea of some co-orbital, the size of Mars, forming, then being deflected by Venus and Mercury into hitting a proto-Earth. Too much of a good thing for NASA's graphic designers I fear. I actually prefer Darwin's theory. A proto-Earth, a gas giant the size of Jupiter, throws out Mars as it condenses, and needs to dump angular momentum.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #29 - 11/02/15 at 23:34:20
 
Quote from Bob on 11/02/15 at 23:04:29:
frankuitaalst, do your co-orbital planets start out as that? We have just a lot of dust which needs to form into a planet. So does it do that, then migrate; with several others into the co-orbital configuration?

I've never been a great fan of the idea of some co-orbital, the size of Mars, forming, then being deflected by Venus and Mercury into hitting a proto-Earth. Too much of a good thing for NASA's graphic designers I fear. I actually prefer Darwin's theory. A proto-Earth, a gas giant the size of Jupiter, throws out Mars as it condenses, and needs to dump angular momentum.

In the simulation above I made I just wanted to examine the stability of coorbitals . They seem to be stable in SMA , ie. once being created they seem to stay where they are . So , yes , I originally put them all at 60° in one orbit and let them evolve over time.  
The sim doesn't take into account in any way accretion of dust or whatever .  
 
I could have done this with 6 Jupiter sized planets also at Jupiters distance to the sun. I guess the result might be the same except for the time scale.  
At Jupiters distance to the sun the coorbitals might evolve slower .  
Edit : IIRC : I somewhere read that there is a maximum of coorbital bodies which holds the system stable . Fi. if the mass concentration gets to high the system experiences the influence of Mutual potential energy which results in instability . The above simulation is well under this limit .
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #30 - 11/03/15 at 00:57:29
 
I think we might have to pencil in the question of induction heating of asteroids as well. The young Sun can do that but I've no idea about f type stars, do they, f types, switch off that evolutionary phase earlier, or later?
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #31 - 11/03/15 at 06:39:28
 
(Mass of planet + trojans) <~4% mass of star.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #32 - 11/03/15 at 06:43:30
 
Yes 1/28 it was I think . 4% gives for Jupiter sized planets about 40 bodies.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #33 - 11/03/15 at 07:09:24
 
Quote from frankuitaalst on 11/03/15 at 06:43:30:
Yes 1/28 it was I think . 4% gives for Jupiter sized planets about 40 bodies.

Anxious to see such a simulation .  Wink
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #34 - 11/03/15 at 13:55:13
 
I performed some simulations having some Jupiter sized planets around our sun in a coorbital orbit at 5.2 AU , meaning several Jupiters in the same orbit , but separated by fi. 60° in their orbit .  
To my surprise I don't get stable orbits with a lot of Jupiters , except for the case in which I put an extra Jupiter in the L4 and the L5 lagrangian point , thus creating trojans the mass of Jupiter itself .  
 
So , returning to the Original Post of Bob : trojans may partially explain the big dips observed . I tried to introduce large trojans in order to simulate the big dips observed , but there seems to be a limit of the number of large bodies  
 
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #35 - 11/03/15 at 15:23:13
 
Regarding ~4%, I found better numbers.
If the combined mass of the planet and its trojans is between 0 and 2.85%, the system will be stable.
If the combined mass of the planet and its trojans is between 2.85% and 3%, the system will not be stable.
If the combined mass of the planet and its trojans is between 3.1% and 4% the system will be stable.
If the combined mass of the planet and its trojans is greater than 4% the system will be unstable.
 
This is from a discussion I had 8 years ago on the Cosmoquest forum.
http://cosmoquest.org/forum/showthread.php?58590-Orbit-of-Earth-changes
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #36 - 11/03/15 at 23:33:44
 
Thanks for the info Tony  
I've also found this :  
http://www.math.cornell.edu/~templier/junior/final_paper/Thomas_Greenspan-Stabil ity_of_Lagrange_points.pdf
pointing to a ratio m1/m2 > 24.9 , which is indeed 4%  
After restoring the broken links the equilateral 2 planet configuaration is analysed here :  
http://iopscience.iop.org/article/10.1086/341173/pdf;jsessionid=EDB1DB457C20A295 660CC4118B3F296E.c2.iopscience.cld.iop.org
indeed pointing out to a value of mplanets/Msun = 0.03812
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #37 - 11/04/15 at 09:02:11
 
I suppose we can simply wait for SETI's announcement, which they say is forthcoming (six weeks). Though they do seem to like a lot of showmanship, and they might be announcing that they couldn't hear any radio alien chat. They wouldn't have anyway, it's too far away, and it would be tight beam. So, pointing a radio array at the star is to look at its radio spectrum, and thy must be looking closely at it in the optical as well. The very fact that it doesn't have any close in gas giants, yet the star has lost angular momentum, has to mean it's going to be a major press conference when it comes.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #38 - 11/04/15 at 09:05:33
 
I had hoped that that guy Anders Sandberg, might have joined here, as he does seem to know his stuff. Early days,he miht just be slow at reading his blog replies.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #39 - 11/04/15 at 13:55:31
 
Quote from Bob on 11/04/15 at 09:02:11:
. The very fact that it doesn't have any close in gas giants, yet the star has lost angular momentum, has to mean it's going to be a major press conference when it comes.    

Not sure what you mean by the statement about the gas giant . Didn't know the star lost angular momentum . Do you have a reference ?  
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #40 - 11/04/15 at 15:22:56
 
Here's the result of my best simulation I can come up with in the case of Trojans :  
 
Suppose the light curve of the planet is due to a transit of  major Jovian Planet , followed by some Trojans , as depicted in the picture hereby .
I "played" with some initial settings of the system ( coorbitals) and limited myself to  a trailing and a leading Jovian planet of the same mass as the primary .      
In the setup the following system is stable : A Jovian planet at 5.2 AU , having 0.4% Solar mass ( NOT 4% !) , followed by a trojan of equal mass at 60° and behind a trojan of equal mass at 60° . So total mass of all bodies being 1.2% of the solar mass.  
Replace the trojans by some bunch of smaller bodies , and maybe we get the light curve observed ?  
( I wished I had come up with a bigger ratio of Jovian Mass to Solar Mass , but this seems not to be stable ) ...
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PicN65_KM_3_Jups.jpg
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #41 - 11/05/15 at 02:12:56
 
It's rotation is about 27 times faster than Sol's. It hasn't dumped as much angular momentum into its planetary disk as our sun has but that's okay. A star in its collapse becomes unstable, it dumps about half its mass into the equatorial plane, and continues contracting. When it "switches on", it drives most of the light stuff out. With this star there's going to be more mass in the disk but not enough to brake the star's momentum as effectively as our solar system has.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #42 - 11/07/15 at 08:57:19
 
As a demonstration of a potential Trojan System around the mysterious star :  
 
http://orbitsimulator.com/gravitySimulatorCloud/simulations/1446914152802_Jupite r%20Trojan.html
 
Simulation consists of :  
- the central star 1.43 Ms
- two Jupiter planets , having each 5 MJup ,  at 6AU distance , sharing one orbit .
- one of them has 7 Earth sized moons around it .  
 
The systeem seems to be stable .  
Edit : link above doesn't seem to work ; I'm pretty sure I posted it with the Save feature , also providing some description  . Can't find the sim either in the list of simulations.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #43 - 11/07/15 at 09:55:18
 
You lost the .html when you copied it.  I fixed it for you.
 
It's in the list. Refresh your page.
http://orbitsimulator.com/gravitySimulatorCloud/simulations/
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #44 - 11/07/15 at 13:44:21
 
Thanks . I was worried not to see the sim in the list and configured the sim twice . Now I see I have to refresh my browser in order to see changes.  
Both are there . You can delete one of them if you want.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #45 - 11/09/15 at 23:02:02
 
I think that we need a cloud of Trojans which are going to be some percentage of the mass of the rocky core of our Jupiter. That's thought to be between ten and twenty Earth masses. So let's say we have (5e 25)^0.6 = 2.6e 15kg Which is in the ball park for the total mass of our Trojans plus Hildas. The reason for that is that one Jupiter mass planet forms from the accretion disk and stops the formation of other Jupiters at the Lagrange points. Most of the mass is hydrogen and is lost.
 
Now for the 22% dip, we want a filter. It's pretty large but also fairly thin, and its angle to the star,at the distance we're looking at it, is going to be in fractions of a second of arc. Using this equation from Wiki, I get a refractive index of about (1.02)^2 So what can be happening is that the star's light is being absorbed by an asteroid then re-emitted at longer wavelength, basically it's being bounced around inside the filter.  
 
 
 
https://en.wikipedia.org/wiki/Interference_filter
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #46 - 11/14/15 at 00:21:47
 
Rather by chance I came up to the following article , googling for "light transit curves" :
 
http://www.desdemonadespair.net/2015/10/did-kepler-space-telescope-discover.html
 
As far as I can interprete this article the curves are strange , but not unexplicable .  
Some planets around this star may be involved .
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #47 - 11/15/15 at 01:30:57
 
Hmm, I think this is a bit of a stretch. A Pre-Main Sequence M type star with a 3 times Jupiter mass planet, is not that far off being a Brown Dwarf binary. It's not going to much like an F type Main Sequence star; I would have thought. But we should look at this anyway, for belt and braces reasons.  
 
https://en.wikipedia.org/wiki/Von_Zeipel_theorem
 
We could also look at Vega, for comparisons, as we see Vega pole on, so because of its oblateness, we see it as being bigger than it should be. WTF's spin is about 27 times faster than our Sun, so it's going to be oblate, but I'm not happy with the idea of a Main Sequence star where the planets are at wild angles to the star's equatorial plane.
 
Then; even if we accept such inclinations, and gravitational pole darkening; we still have the problem that Jupiter sized planets will only dim the star by about 1%. I can't see how it can be other than a bunch of asteroids. I suppose we could look at the star's receding limb; and with it the star's barycentre; which can be outside of the star's radius at times. That might give us some idea of the asymmetry.    
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #48 - 11/22/15 at 14:57:53
 
Heavy stuff the Von Zeipel theorem ; this goes beyond my competence ...
Concerning the "need" to have a bunch of asteroids involved here : I don't quite understand how a bunch of asteroids could account for a darkeing of the sun's surface more than a really big gas planet does , because normally the mass ( and therfor the eclipting surface) is much smaller than what a gasg iant can accomplish , or do I miss something ...?
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #49 - 11/25/15 at 01:07:29
 
It's to do with the surface area to volume ratio. If you could take Mercury apart and create "panels" of about a km square, and put them into a swarm, then they would dim the light reaching Earth much more than the transit of Mercury does.
 
Let's say we have about half a million 1km diameter lumps of rock at a Trojan point, then it can act like a thin film. Then it would be shifting the wavelength of the light rather than the intensity.  
 
Lambda_1 = Lambda_0 sqrt(1 - sin^2 (theta) / n^2) Where n is a refractive index. Here n is going to be about 1.027, which is quite modest.
 
Think of it as being like those printed bus shelters/buses , where the passengers can see out but people outside see an advert. All done by having little dots of colour, very close together.  
 
(Edited) Of course this would also apply to Tony's point about a super Saturn ring system,in that it too could be clear of too much dust.
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Re: KIC 8462852[1] (unofficially called WTF)
Reply #50 - 11/25/15 at 04:58:31
 
The latest comments on this. They still sound none the wiser.
http://phys.org/news/2015-11-astronomers-comet-fragments-explanation-mysterious. html
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