Science

discussion

RINGS & MOONS

Started by ggccg
Default_user
over 6 years ago

Re: APH22714177. This is a most unusual transit. I've seen little peaks within transits before and they've always been explained as the transiting object occulting a star spot on the primary resulting in a temporary brightening. But two brightenings symmetrically around a central dimming is perplexing.

The primary itself is spotted, most likely, and the 4% variation in brightness suggests a fairly large system of spots, and it rotates with a period of ~12 days.

I've detrended each transit and averaged them to get this:

The features seem too consistent to be instrument error, and the spacing, ie. timing of these variations are just too unusual, and calls out for some explanation.

The difference between the peaks and valleys (min = 0.9750, max = 0.9765) is 0.0015 which by itself corresponds to a 0.8 RJ object. So could the transiting object actually be a binary, a brown dwarf with a super-Jupiter companion locked in a very close orbit (peak to peak ~ 3 hrs) ? I originally thought it might be feasible, as such a binary could be stable, the two objects are closer in mass to each other, and they orbit around their barycenter, which in turn orbits the larger host at a distance of 0.179 AU (close, but not that close).

Here's how the binary system might look like, drawn to scale, the brown dwarf is 3.2 RJ and the 'moon' or companion is 0.8 RJ.

However, when I calculated the separation for a period of 3 hours, it just doesn't work, the planet is too close, inside the Roche limit, and would be torn apart by tidal forces. For this configuration to work, the period has to be just over 4 hours.

Furthermore, I was also skeptical, as Paul pointed out, the configuration may not be stable - and it's not likely to get such an alignment just right so the dip is always centered, which means some sort of orbital resonance.

So we still need a better explanation.

Default_user
over 6 years ago

another possible long transit! http://talk.planethunters.org/objects/APH23030115

Default_user
over 6 years ago

@toniscarmato

I'm not sure if it's a transit. If it is, then yes, it looks like it has some smaller dips to the left and right of it. But when zooming out, I think the larger dips just at left or right (17.7, 25.5) look more like transits. Personally I think the star is pretty quiet and the remaining features are probably just starspots.

Default_user
over 6 years ago
toniscarmato in response to zoo3hans

zoo3hans:

@toniscarmato

I'm not sure if it's a transit. If it is, then yes, it looks like it has some smaller dips to the left and right of it. But when zooming out, I think the larger dips just at left or right (17.7, 25.5) look more like transits. Personally I think the star is pretty quiet and the remaining features are probable just starspots.

yes i saw the smaller dips, by the way the beaviour look like good!

Default_user
over 6 years ago

@kianjin

What if we assume that the body transiting the brown dwarf has a ring system as suggested by the bumps in brightness on each side of the event (a la your post re: APH10085918). Is it possible that the refracted/reflected light from the rings is blurring the entry/exit points of the transit and the duration might actually be 4 hrs. or more instead of the 3 measured from peak to peak? See the typical transit image I posted at the beginning of this discussion. If you measure peak to peak there, you get your 4 hrs. Perhaps something was lost in the smoothing and averaging?

Default_user
over 6 years ago

Here's another large planet transit that appears to contain what may be a moon transit during the planet transit.

Default_user
over 6 years ago

@ggccg

What about 122.5-123.1 being the 2nd transiting of the moon, after passing behind its planet? If it's "leading" the planet at 121.7, it might have to "swing around" behind it, which would take considerable more time ... hence the longer dip.

BUT I think the additional depth of the transit is way too big for a moon - it looks pretty much 2/3 as big as the supposed planetary transit?!

Default_user
over 6 years ago

To add my 0,02€ to the APH22714177 (KID10616571) discussion:

Did you notice the small peaks are not only 6 squares apart in kianjins detrended and averaged lc, but they continue on the flank of the big transit, and are exactly congruent with it's upper edges? (start counting at "35" and go left, right .. you'll see what I mean.) But I wasn't able to find any trace of them outside the big transits, so it must be some effect that is tied to the transiting object. (we all agree 'bout that anyway, right?)

The Kepler teams suggests this is an EB .. but where are the secondary transits? I have spotted some very slight, long transit candidates which might in fact be occultations (80.6-82.6, ?? - 107.9); there might be more, but they're hard to spot.

I found some more transit candidates (12.85-13.15, 39.24-39.34, 60.385-60.50); though I'm not sure if there can be additional planets in such a system at all?!

And finally an inverse transit candidate, though it might be a glitch (68.58-68.86)

Default_user
over 6 years ago
ggccg in response to arralen

arralen:

I had read the big transit to be from 121.5 (just before the event I marked) to about 123.1. It looks more defined not so zoomed, but I wanted to show what I marked. Your point about the depth is well taken. I don't have the math/science background to figure this all out, so I'm just posting for consideration what seems interesting as I find it. I am very pleased that this thread has drawn the attention of some serious thinkers. I think it's just a matter of time before we make some good finds. We just have to look a little closer at the data.

Default_user
over 6 years ago

I think this candidate might also have rings : APH21122898

rings3

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