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KIC 8462852 is a Very Unusual Star


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#1 Smersh

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Posted 15 October 2015 - 04:55 AM

It seems to have a whole bunch of something going around it that so far hasn't been explained.

The Bad Astronomer's take on it is here:

http://www.slate.com...t_baffling.html

(Which reminds me, I need to get a new vacuum cleaner ...) 


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#2 Dewtey

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Posted 15 October 2015 - 06:01 AM

Definitely an intriguing star.  I'll go out on a limb here and suggest that it's a binary star system that in the past had one of the stars siphoning off the material of the other, and that one has gone cold leaving one heck of an asteroid belt and debris cloud.


Or, it might be aliens building a Dyson Ring...  :whistle:


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#3 Smersh

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Posted 15 October 2015 - 07:18 AM

Definitely an intriguing star.  I'll go out on a limb here and suggest that it's a binary star system that in the past had one of the stars siphoning off the material of the other, and that one has gone cold leaving one heck of an asteroid belt and debris cloud.


Or, it might be aliens building a Dyson Ring...  :whistle:

If it was a young star, then I guess it's quite likely to have quite a bit of debris going around it. But it's not a young star, so maybe that binary explanation is possible. 

Re Dyson Ring  - word is that the folks at SETI are getting quite interested and in the process of pointing some hardware at it, to see if any unusual signals can be detected. Awaiting results ... 


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#4 CommonMan

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Posted 15 October 2015 - 08:09 AM

Keep us informed, Smersh old buddy.



#5 silylene

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Posted 15 October 2015 - 08:12 AM

Well, if we want to get into the woo speculations:

Incomplete Dyson sphere  (under construction?)

Multiple ringworlds around the star, differing in width and diameters and tilts.

Transgalactic communication device (some sort of signal code)



#6 Dewtey

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Posted 15 October 2015 - 08:32 AM

Folks see their star dying so are moving their civilization?


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#7 Smersh

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Posted 15 October 2015 - 08:55 AM

Keep us informed, Smersh old buddy.


I'm relying on folks like the BA to keep me informed CM, but I will try!

Re Dewtey's theory about a possible binary companion in the past that sucked off a load of debris and that's what we are now seeing - the infrared footprint doesn't match this, as mentioned by Phil Plait in the link in my OP. 
 

... The problem with that is that there’s no excess of infrared light from the star. Dust created in such impacts warms up and glows in the IR. We know how much IR stars like KIC 8462852 give off, and we see just the right amount from it, no more. The lack of that glow means no (or very little) dust ...



http://www.slate.com...t_baffling.html


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#8 Dewtey

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Posted 15 October 2015 - 10:23 AM

Actually, I was thinking that the 'doner' star was cold and not contributing any more of it's mass.


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#9 TheBigCat

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Posted 15 October 2015 - 02:48 PM

Well, we looked at it for a long time and we check out a bunch of different theoretical models but nothing fit our observations until someone suggested aliens...

 

In so many words.

 

 

If nothing else this highlights the patience that some within SETI have to pounce with the "A" word. Watch though... In a few years someone will come up with a workable model which doesn't involve civilizations out of a Larry Niven novel and will be completely discounted by the general public at-large, i.e., the Fox Mulder Fan Club.



#10 brellis

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Posted 15 October 2015 - 04:16 PM

Could multiple large planets happen to transit in various combinations, resulting in a set of huge dips?

Imagine if two or three aligned in transit during the Kepler observations.

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#11 Ath3na

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Posted 15 October 2015 - 04:23 PM

How about gravitational lensing from a nearby dark [compact] object, or objects?


The data's pretty noisy (lacking expected orbit patterns) for that, Brel.  But a wobbling compact object could have odd lensing effects.


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#12 vog

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Posted 15 October 2015 - 05:22 PM

The reference talked about comets, but I think there is a fatal flaw with the comet idea.  Sooner or later, Kepler would have to see a comet traverse the far side of the star.  The effect of that would be instead of a startling dip in brightness, there would be a 'startling' rise in brightness.  Kepler has seen planets reflecting light back at us from the far side of their intervening stars, if this odd stellar system is beset with outsize comets, there is nothing special about the direction towards us, therefore, a comet would sooner or later be behind the star and reflect extra light our way.  The published light curve shows no such feature(s).


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#13 silylene

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Posted 15 October 2015 - 08:01 PM

Could multiple large planets happen to transit in various combinations, resulting in a set of huge dips?

Imagine if two or three aligned in transit during the Kepler observations.

 

I was going to suggest a complex variant of your idea, but I have more thoughts on this.

 

We need to account for a few facts here:

It can eclipse at least 22% of the star

There are multiple large objects, and each object must have orbital periods at least several years (because no periodicity was noted within the observational span, which means none of them repeated exactly, at least none repeated with the same obscuration).

Some of the large objects look 'grouped' in their obscuration, in the sense that the eclipses were in very close time proximity.

There is also a small object which orbits with a 20d period.

There is a 0.88d cycle which could be a starspot, which assume the star revolves around its axis a fast 0.88d (it isn't a pulsar).

Infrared data doesn't support collisions or even comets.

 

Speculation which doesn't involve alien constructs or woo hypotheses:

The star has several large (presumably gas giant) planets which orbit it at various distances with periods of many years, so each planet may have only been observed once.

The large gas giant planets are ringed systems with vary opaque rings, like Saturn, but no noticeable ring gaps.  The planet with the 22% obscuration has a HUGE dense ring system that can eclipse 22% of the star's area.

The large gas giant planets have very large exomoons orbiting them.  (this accounts for the secondary obscurations observed in close time proximity to the major obscurations at 1500-1600 days).

Maybe the large gas planet at 793d and 1520d is the same planet, just the ring angle changed, and at 1519d an exomoon was observed with it.

 

 

 

star_alien_dips.png.CROP.original-origin

 

star_alien_dips2.png.CROP.original-origi

More data from Kepler show the starlight going up and down on a timescale of 20 or so days (the more frequent 0.88 day cycle is most likely a starspot rotating into and out of view).



#14 Mee_n_Mac

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Posted 17 October 2015 - 05:30 PM

Could there have been anything much closer, perhaps in our solar system, that in a freak alignment blocked Kepler's view for the large non-periodic dips ?
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#15 StarRider1701

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Posted 21 October 2015 - 08:39 AM

No MnM, I don't think so.  They watched this star long enough to establish periodic frequency, so while your 'freak alighment' may have happened one time, it won't explain the recurring transitions.



#16 silylene

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Posted 21 October 2015 - 10:44 AM

I still haven't seen anyone suggest that the eclipsing objects are exoplanets with large opaque rings (super-Saturns), and also some have exomoons.  I still think it is a possibility.

 

Hopefully I will see my idea come be proposed in some future paper.

 

I have read the original paper.  It is quite interesting and not behind a paywall.



#17 StarRider1701

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Posted 22 October 2015 - 04:51 AM

I don't know Silylene, 22% is pretty huge.  By comparison, a Jupiter would be around 1%.  While I don't yet speculate Aliens, I do think there may be something a bit more exotic than a few Jupiters with big rings.  Maybe something like a small black hole which distorts the light, making it look bigger to us than it is.  If it is dormant (not eating) and in a stable orbit around the star, that might explain the strange stuff.  I don't think we've seen something like that before...



#18 silylene

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Posted 22 October 2015 - 07:51 AM

I don't know Silylene, 22% is pretty huge. .....

 

The amount of obscuration would require a ringed system about 2-3x the size of Saturn if you calculate it out, assuming the rings are tilted about 90 degrees (like Uranus, or Pluto-Charon).

 

In our solar system, 75% of the larger planets have rings.  25% of the larger planets have an axis tilted almost 90 degrees from the ecliptic.  I don't think it is too hard to image finding a star with 3 super-Saturns, each highly tilted.  It's a matter of statistical odds.   Yes it would be uncommon to find 3 tilted Saturns, but out of the thousands of stars found to have exoplanets by Kepler, so far only one is like this (which I would say is 'uncommon', as expected).

 

By the way, I assume you recall the massive rings around exoplanet J1407B discovered in 2012?  (200x bigger rings than Saturn)  LINK



#19 StarRider1701

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Posted 23 October 2015 - 04:42 AM

Lots of cool speculation.  Wonder how many decades it will take for us to know for sure...?



#20 silylene

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Posted 23 October 2015 - 07:41 AM

We need to build and launch another new, improved Kepler.



#21 StarRider1701

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Posted 26 October 2015 - 05:42 AM

Wonder when someone will think of putting an observatory on the Moon?  I think one on either the north or south poles would be neat, with a wall of solar panels around it and an open sky, a big telescope on the Moon could show us lots of great stuff.  Wonder how much of it could be made with lunar materials...?



#22 Dewtey

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Posted 26 October 2015 - 07:04 AM

Not sure which would be more expensive, getting a 'scope up there in pieces, or getting the equipment to manufacture the scope up there...  Never mind, the glass grinder alone has to be larger than the mirror, so that answers my question.


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#23 Mee_n_Mac

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Posted 27 October 2015 - 05:02 PM

A low frequency radio-telescope on the Moon makes somewhat more sense. The surface can be used to hold the individual antenna elements, saving the trouble of having to put that part into space (or construct in situ). And the far side is quiet.

https://www.newscien...for-telescopes/

http://news.mit.edu/.../moonscope-0215

200908311113095449_0.jpg?itok=FkZS0Aae

But this a bit OT.
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#24 Dewtey

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Posted 27 October 2015 - 05:37 PM

And the far side is quiet.---

 

At least it's quiet when not pointed at the Sun.  Which is 2 weeks out of 4.


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#25 StarRider1701

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Posted 02 November 2015 - 04:28 AM

Not sure which would be more expensive, getting a 'scope up there in pieces, or getting the equipment to manufacture the scope up there...  Never mind, the glass grinder alone has to be larger than the mirror, so that answers my question.

The scope wouldn't need to be any bigger than our current orbital telescopes, the more eyes we have out there, the more we'll be able to see.  Right now we're limited only by the very low number of off Earth telescopes, and a fixed scope on the ground may have advantages over our orbital ones.





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