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KIC 8462852 Observations
JRehling
post Oct 15 2015, 04:45 PM
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Kepler found one very, very strange case:

http://www.theatlantic.com/science/archive...-galaxy/410023/

In a nutshell, while Kepler was observing it, the star (larger and brighter than the Sun) exhibited four dimming events that took place at irregular intervals, blocked a lot more light than a Jupiter-sized planet would block, and had a "shape" that varied in all four cases and did not resemble a planet.

This case is attracting some wild speculation… in fact, it is seemingly certain that something wild must be going on; it's just a matter of which wild scenario is the correct one.

If I had to throw my hat in the ring, I'd guess that a distant collision and breakup has placed big swarms of matter into a very long-period orbit. But there's no hypothesis that's been offered that doesn't seem problematic.
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silylene
post Oct 16 2015, 02:43 PM
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We need to account for a few facts here (see the paper for many more):

Eclipses at least 22% obscuration of the KIC 8462852 star
There are multiple large eclipsing 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 occurred in very close time proximity.
There is also a small object which orbits with a 20d period.
There is a 0.88d cycle is likely a starspot, which assume the star revolves around its axis a fast 0.88d.
Infrared data doesn't support collisions or even comets.

My speculation which doesn't involve alien constructs or other woo hypotheses:

The star has several exoplanets which orbit it at various distances with periods of many years, so each exoplanet may have only been observed once in the data set.
Some of the exoplanets are ringed systems with very opaque rings tilted out of the ecliptic with no noticeable ring gaps. The exoplanet at 793d with the 22% obscuration has a HUGE dense ring system that is inclined such that it can eclipse 22% of the star's illumination as see from earth.
Some of the exoplanets have very large exomoons orbiting them. (this accounts for the secondary obscurations observed in close time proximity to the major obscurations, for example in the data between 1500-1600 days).
Maybe the large exoplanet at 793d and 1520d is the same exoplanet, just the ring angle changed, and at 1519d an exomoon was observed with it.
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JRehling
post Oct 16 2015, 04:27 PM
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QUOTE (silylene @ Oct 16 2015, 07:43 AM) *
My speculation which doesn't involve alien constructs or other woo hypotheses:
[...]
Some of the exoplanets are ringed systems with very opaque rings tilted out of the ecliptic with no noticeable ring gaps.


The third event, at 1541 days, is very intriguingly symmetrical: It has three peaks, with the two outer ones being approximately equal in depth and distance from the larger, central one. That makes me wonder about a ringed planet.

But the other three events don't show that pattern. Event #1 is single-peaked and quite smooth, while Event #4 is double-peaked. Event #2 is pretty messy: It has three peaks, but no symmetry.

So I wonder if Event #3 is due to a ringed planet with the planet and rings participating, and Event #4 due to a ringed planet with only the apsa of the rings participating, and the planet "missing" the star during the event.

Keep in mind that for something opaque to cause a dip of 22%, for a star with 1.58 times the radius of the Sun, the cross sectional area of the transiting object has to be at least 55% the cross section of the Sun, or about 55 Jupiters' worth of cross section. This is a big object or set of objects! A planet + ring system would have to have at least 4 times the diameter of Saturn's rings to accomplish this, like rings extending from Jupiter's cloud tops out to Europa or from Saturn's cloud tops out to Rhea.

And that scenario with rings that we see face-on from Earth would be provided only if the rings were perpendicular to the planet's orbit, which is unlikely to occur by chance; any deviation from that geometry would require a still larger ring system to provide the observed darkening.

That might just work if we only had one such event to explain, but four of them means that there would be at least three different giant planets with three gigantic ring systems. I can't see how that would happen.
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HSchirmer
post Oct 17 2015, 12:41 PM
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QUOTE (JRehling @ Oct 16 2015, 05:27 PM) *
...
Keep in mind that for something opaque to cause a dip of 22%, for a star with 1.58 times the radius of the Sun, the cross sectional area of the transiting object has to be at least 55% the cross section of the Sun, or about 55 Jupiters' worth of cross section. This is a big object or set of objects! A planet + ring system would have to have at least 4 times the diameter of Saturn's rings to accomplish this, like rings extending from Jupiter's cloud tops out to Europa or from Saturn's cloud tops out to Rhea.
...
That might just work if we only had one such event to explain, but four of them means that there would be at least three different giant planets with three gigantic ring systems. I can't see how that would happen.


Eh, guess we might be seeing the system during a late heavy bombardment / nice-model period of orbital chaos?
Hmm, two hot jupiters swapping places, each dragging along debris fields of trojans. In the nice model, is there a scenario where Jupiter and Saturn don't scatter, but merge, or end up a close binary; basically something huge and gaseous and opaque, that might be {relatively} cool, at least in contrast to simply smashing two earth sized planets together?

Thinking about outside effects, what happens if a brown dwarf binary, e.g. Luhman 16, drifts into the system?
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Posts in this topic
- JRehling   KIC 8462852 Observations   Oct 15 2015, 04:45 PM
- - ZLD   Yeah, I will be patiently waiting and excited if t...   Oct 15 2015, 08:42 PM
- - scalbers   Could this be like some of the dense clouds that e...   Oct 15 2015, 10:08 PM
- - ngunn   Kepler is designed to look for transits - but how ...   Oct 15 2015, 10:09 PM
|- - JRehling   The research paper says that the properties of the...   Oct 15 2015, 10:29 PM
- - ZLD   I think the biggest peculiarity that rules out a l...   Oct 16 2015, 12:26 AM
|- - JRehling   QUOTE (ZLD @ Oct 15 2015, 05:26 PM) I thi...   Oct 16 2015, 04:27 AM
- - nprev   What spectral class is this star? Higher rotation ...   Oct 16 2015, 04:44 AM
|- - JRehling   QUOTE (nprev @ Oct 15 2015, 09:44 PM) Wha...   Oct 16 2015, 04:10 PM
- - ZLD   @JReling: Thanks for the correction. I skimmed it ...   Oct 16 2015, 05:28 AM
- - silylene   We need to account for a few facts here (see the ...   Oct 16 2015, 02:43 PM
|- - JRehling   QUOTE (silylene @ Oct 16 2015, 07:43 AM) ...   Oct 16 2015, 04:27 PM
|- - HSchirmer   QUOTE (JRehling @ Oct 16 2015, 05:27 PM) ...   Oct 17 2015, 12:41 PM
|- - silylene   QUOTE (JRehling @ Oct 16 2015, 05:27 PM) ...   Oct 21 2015, 03:33 PM
|- - JRehling   The biggest problem with the rings hypothesis is t...   Oct 21 2015, 04:04 PM
|- - HSchirmer   QUOTE (silylene @ Oct 21 2015, 03:33 PM) ...   Oct 21 2015, 04:31 PM
|- - HSchirmer   QUOTE (silylene @ Oct 21 2015, 03:33 PM) ...   Jan 27 2016, 02:20 AM
|- - Gerald   QUOTE (HSchirmer @ Jan 27 2016, 03:20 AM)...   Jan 27 2016, 11:11 AM
||- - HSchirmer   QUOTE (Gerald @ Jan 27 2016, 12:11 PM) De...   Jan 27 2016, 02:16 PM
|- - JRehling   QUOTE (HSchirmer @ Jan 26 2016, 07:20 PM)...   Jan 27 2016, 06:26 PM
- - scalbers   Here's a web page that helps explain Epsilon A...   Oct 17 2015, 01:17 PM
- - ngunn   Accepting the idea of eclipsing objects of some ki...   Oct 17 2015, 08:54 PM
|- - HSchirmer   QUOTE (ngunn @ Oct 17 2015, 08:54 PM) Acc...   Oct 18 2015, 12:07 PM
|- - JRehling   Interesting thoughts, nprev and HSchirmer. The fir...   Oct 19 2015, 08:12 PM
|- - ngunn   QUOTE (JRehling @ Oct 19 2015, 09:12 PM) ...   Oct 19 2015, 09:19 PM
|- - HSchirmer   QUOTE (JRehling @ Oct 19 2015, 09:12 PM) ...   Oct 19 2015, 09:26 PM
|- - JRehling   Comet Hale-Bopp's tail had a maximum length of...   Oct 20 2015, 02:09 AM
|- - JRehling   Another thought: A comet seen transiting its star ...   Oct 20 2015, 05:46 PM
|- - HSchirmer   QUOTE (JRehling @ Oct 20 2015, 06:46 PM) ...   Oct 20 2015, 06:50 PM
- - Hungry4info   Look at the light curve. A dark sphere transiting ...   Oct 20 2015, 12:48 AM
- - Rittmann   I was wondering... How much obscuring could happe...   Oct 20 2015, 08:49 PM
- - ngunn   I'm still not buying the comets idea, sorry.   Oct 20 2015, 09:54 PM
- - Explorer1   But as long as the parent planet's spin axis i...   Oct 21 2015, 04:13 PM
|- - Mongo   QUOTE (Explorer1 @ Oct 21 2015, 04:13 PM)...   Oct 21 2015, 04:35 PM
|- - HSchirmer   QUOTE (Mongo @ Oct 21 2015, 04:35 PM) But...   Oct 21 2015, 05:30 PM
- - Explorer1   And now a star getting 40% of its light blocked: h...   Oct 21 2015, 05:43 PM
- - silylene   My concept is that the rings are not edge-on to ea...   Oct 21 2015, 06:57 PM
|- - JRehling   QUOTE (silylene @ Oct 21 2015, 11:57 AM) ...   Oct 22 2015, 12:40 AM
|- - HSchirmer   QUOTE (JRehling @ Oct 22 2015, 12:40 AM) ...   Oct 23 2015, 12:33 PM
- - alan   The asymmetry of one of the transits reminds me of...   Oct 21 2015, 07:33 PM
- - AndyG   Huge, dense and opaque ring systems that are tilte...   Oct 22 2015, 08:37 AM
|- - JRehling   QUOTE (AndyG @ Oct 22 2015, 01:37 AM) Hug...   Oct 22 2015, 08:54 AM
- - Hungry4info   The relevant question is angular resolution, but t...   Oct 23 2015, 01:10 PM
- - Explorer1   I was browsing the extreme exoplanets list on Wiki...   Oct 31 2015, 02:17 AM
- - Hungry4info   No, it isn't right at all. The original paper ...   Oct 31 2015, 04:27 AM
- - Explorer1   Yes, just as I suspected. I did a quick search t t...   Oct 31 2015, 06:52 AM
|- - JRehling   There are probably some planets made largely/entir...   Nov 2 2015, 05:01 PM
|- - HSchirmer   QUOTE (JRehling @ Nov 2 2015, 05:01 PM) ....   Nov 3 2015, 03:44 AM
|- - JRehling   QUOTE (HSchirmer @ Nov 2 2015, 08:44 PM) ...   Nov 3 2015, 04:20 PM
|- - HSchirmer   QUOTE (JRehling @ Nov 3 2015, 04:20 PM) T...   Nov 3 2015, 04:59 PM
|- - JRehling   QUOTE (HSchirmer @ Nov 3 2015, 09:59 AM) ...   Nov 3 2015, 07:19 PM
- - Hungry4info   Besides, we know of numerous pulsar+WD binaries.   Nov 3 2015, 07:48 PM
- - nprev   JRehling is correct. Please stay on topic.   Nov 4 2015, 02:24 AM
- - ZLD   JPL posted a short article yesterday further sugge...   Nov 25 2015, 05:36 PM
- - Mongo   Paper is up on ARXIV now: KIC 8462852 - The Infra...   Nov 26 2015, 01:49 AM
- - Mongo   KIC 8462852 Faded at an Average Rate of 0.165+-0.0...   Jan 14 2016, 02:22 AM
|- - JRehling   I wonder if the reality is that the dimming occurr...   Jan 14 2016, 10:09 PM
- - nprev   Interesting. First thing this makes me think of is...   Jan 14 2016, 02:33 AM
|- - Mongo   QUOTE (nprev @ Jan 14 2016, 02:33 AM) Int...   Jan 14 2016, 02:54 AM
- - nprev   Hmm. Curiouser indeed. Almost seems like it has to...   Jan 14 2016, 03:00 AM
- - ZLD   Clearly just Starkiller Base finishing checkout te...   Jan 14 2016, 03:07 PM
- - Gerald   Black holes (besides hypothesized primordial ones)...   Jan 14 2016, 04:16 PM
- - Mongo   I noticed this statement from the Bradley E. Schae...   Jan 16 2016, 06:04 PM
- - Mongo   Okay, I've decided to download the full archiv...   Jan 16 2016, 06:39 PM
|- - JRehling   The use of archival data to study the brightness v...   Jan 25 2016, 05:50 PM
|- - HSchirmer   QUOTE (JRehling @ Jan 25 2016, 05:50 PM) ...   Jan 25 2016, 08:26 PM
|- - JRehling   QUOTE (HSchirmer @ Jan 25 2016, 01:26 PM)...   Jan 25 2016, 11:27 PM
|- - dudley   QUOTE (JRehling @ Jan 26 2016, 12:27 AM) ...   Jan 26 2016, 01:47 AM
|- - JRehling   QUOTE (dudley @ Jan 25 2016, 06:47 PM) So...   Jan 26 2016, 08:47 AM
- - Mongo   Attached is a diagram I made using 2-year bins. I ...   Jan 21 2016, 04:34 PM
- - dudley   KIC 8462852 is reportedly being watched for anothe...   Jan 23 2016, 05:29 PM
|- - HSchirmer   QUOTE (dudley @ Jan 23 2016, 06:29 PM) KI...   Jan 25 2016, 03:53 PM
- - nprev   In order to keep the Kepler topic open for other o...   Jan 25 2016, 11:02 AM
- - dudley   If I recall correctly, the Kepler Space telescope ...   Jan 25 2016, 10:04 PM
|- - JRehling   Kepler found no planets around this star, but that...   Jan 25 2016, 11:29 PM
|- - HSchirmer   QUOTE (dudley @ Jan 25 2016, 10:04 PM) If...   Jan 26 2016, 12:52 AM
|- - JRehling   QUOTE (HSchirmer @ Jan 25 2016, 05:52 PM)...   Jan 26 2016, 09:20 AM
|- - HSchirmer   QUOTE (JRehling @ Jan 26 2016, 10:20 AM) ...   Jan 26 2016, 02:56 PM
- - dudley   I wonder if trillions of comets, especially after ...   Jan 26 2016, 11:25 PM
|- - HSchirmer   QUOTE (dudley @ Jan 26 2016, 11:25 PM) I ...   Jan 27 2016, 12:21 AM
|- - JRehling   During the Kepler era, KIC 8462852's brightnes...   Jan 27 2016, 12:22 AM
|- - stevesliva   QUOTE (JRehling @ Jan 26 2016, 08:22 PM) ...   Jan 27 2016, 05:38 AM
|- - Gerald   QUOTE (stevesliva @ Jan 27 2016, 06:38 AM...   Jan 27 2016, 11:21 AM
- - dudley   I'm aware of two suggestions for how something...   Jan 27 2016, 04:32 PM
- - stevesliva   I have been thinking a lot about the geometry and ...   Jan 27 2016, 08:47 PM
|- - JRehling   stevesliva, I like your idea, although I don't...   Jan 28 2016, 08:08 PM
- - Hungry4info   Occam strikes again. Looks like the long-term dimm...   Jan 28 2016, 01:27 AM
- - Explorer1   So the modern dimming is just comets after all?   Jan 28 2016, 07:32 AM
- - silylene   I still think my earlier proposal (prior thread po...   Jan 28 2016, 02:44 PM
- - dudley   I'd like to see and consider Dr. Schaefer...   Jan 28 2016, 05:31 PM
- - Hungry4info   Response from Schaefer. Rather direct... http://ww...   Jan 28 2016, 10:11 PM
|- - JRehling   It seems like Schaefer has a definitively better g...   Jan 29 2016, 12:24 AM
- - Gerald   Since intrinsic causes are considered unikely, as ...   Jan 29 2016, 09:11 AM
|- - JRehling   A Reddit chat about this phenomenon raised, and su...   Jan 29 2016, 07:37 PM
|- - JRehling   I've found a statement of the problem with an ...   Jan 29 2016, 09:39 PM
- - dvandorn   A perfectly aligned stream of cometary bodies (or ...   Jan 30 2016, 01:38 AM
|- - JRehling   A problem with comets that are dark and far from a...   Jan 30 2016, 03:55 AM
- - Gerald   It cannot be anything likely, since otherwise we w...   Jan 30 2016, 03:17 AM
- - Gerald   The "it cannot be a young star due to the dis...   Jan 30 2016, 11:02 AM
- - dudley   The luminosity class of KIC 8462852 seems to be co...   Jan 30 2016, 05:21 PM
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