KIC 8462852 Observations Options

[JRehling]

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.

[silylene]

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.

[JRehling]

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.

[silylene]

.....
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.

Yes, I am proposing a complicated planetary system with multiple planets with giant ringed systems (at least 3 were observed), plus some planets without ringed systems for the minor occultations, and perhaps even additional exomoons, because if you look closely at the data, there are some shoulder spikes.

And yes, the ring system of the largest one would be 3-5x bigger than Saturn. [I want to remind that exoplanet J1407V has a ringed system 200x larger than Saturn.]

Also ringed object may be more of the rule, rather than the exception. Jupiter, Saturn and Uranus all have rings, although only Saturn has huge opaque rings. Neptune has arcs. At least one and two minor planets have rings (Charliko and 2060 Chiron).

Yes, what I proposed is complicated. I completely agree. And unlikely, I also agree. Perhaps this is why we have only seen *one* of these kinds of systems, it is unlikely?!

But perhaps what I propose remains more likely than other possibilities than odd planet-sized comets which don't absorb in the IR, orbiting rock swarms which are weirdly cold and opaque, or woo proposals which I refuse to consider.

I would like to understand better the long-term stability of large ringed systems in a complex solar system with several large planets and their gravitational interactions. I do suspect that one could have several "super-Saturns" and this would be a stable system.

[HSchirmer]

Yes, I am proposing a complicated planetary system with multiple planets with giant ringed systems (at least 3 were observed), plus some planets without ringed systems for the minor occultations, and perhaps even additional exomoons, because if you look closely at the data, there are some shoulder spikes.

And yes, the ring system of the largest one would be 3-5x bigger than Saturn. [I want to remind that exoplanet J1407V has a ringed system 200x larger than Saturn.]
...

Took a minute to review the posts on this thread, something now jumps out at me.
Rings.

If Tabby's star has comets and KBOs being scattered into the inner solar system, similar to our late heavy bombardment, then impacts on rocky planets could generate hot dust that could cause dips in the starlight. But, near misses should result in rings around the planets. And once you have rings around a planet, that should, in turn, increase the likelihood that the next passing comet will be intercepted as well.
Some work on the idea Did Saturn's rings form during the Late Heavy Bombardment ? mentions that comet flux would be so large that "all satellites smaller than Mimas would have been destroyed during the LHB"




It would seem that a captured comet or KBO disintegrating into a ring won't generate the sort of heat signature that is generally associated with an impact.

And the ring orientation won't necessarily be around the planets equator / that system's ecliptic.
The ring orientation should depend on the angle of approach for the comet/kbo.

[JRehling]

But, near misses should result in rings around the planets.

Probably not. An object that passes close to a planet will not normally be captured by it. It will go into a stellar orbit that intersects the planet's orbit again in the future. Capture is a low-probability event.

If a huge swarm of objects flies by, maybe a significant fraction of them could end up in orbit, but if it's just one or even a dozen, that's not likely.

If a planet already has a sizable satellite, that could also disrupt the formation of any possible ring.

There are a lot of possible permutations. I don't think we're going to resolve them with qualitative pondering.