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KIC 8462852[1] (unofficially called WTF) (Read 16626 times)
Bob
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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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frankuitaalst
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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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Bob
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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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frankuitaalst
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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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Bob
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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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Bob
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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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