### Author Topic: I think that i found something in the kepler mission that is strange.  (Read 1460 times)

#### JHoste

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##### I think that i found something in the kepler mission that is strange.
« on: 06/28/2017 11:14 AM »
the problem that i found, i think i found in the kepler missions is kepler use photometry dims in light of the star to discover planers.

to realize that, the disk if planets must align to Kepler to see the dims from the planets.

now the problem is in the radius to kepler all the planets (planet disks) are in alignment that you see the planets pass the star, this can be happening.

The alignment from kepler to the planet disks is the problem.
« Last Edit: 06/28/2017 04:52 PM by Lar »

#### LouScheffer

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##### Re: I think that i found something in the kepler mission that is trange.
« Reply #1 on: 06/28/2017 12:32 PM »
the problem that i found, i think i found in the kepler missions is kepler use photometry dims in light of the star to discover planers.

to realize that, the disk if planets must align to Kepler to see the dims from the planets.

now the problem is in the radius to kepler all the planets (planet disks) are in alignment that you see the planets pass the star, this can be happening.

The alignment from kepler to the planet disks is the problem.
Yes, you are correct that the alignment of the planet's orbit is not known, and Kepler cannot measure it.

However, this does not affect the  planet's size estimate - the same amount of light is blocked in each case.

#### jebbo

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##### Re: I think that i found something in the kepler mission that is trange.
« Reply #2 on: 06/28/2017 01:10 PM »
Hmm ... that wasn't quite my reading of the question.  I thought it was more about if there were multiple exactly coplanar planets transiting simultaneously ...

Which could happen in the case of planets in a Laplace resonance. However, because the planets have different periods, the transit durations would differ.

FYI, we've seen a number of cases where multiple planets transit simultaneously. But they are not exactly coplanar, so the depths are additive.  [ e.g. one of the transits of Trappist-1 "h" was simultaneous with a transit of either "b" or "c", I forget which ]

--- Tony

#### Bynaus

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##### Re: I think that i found something in the kepler mission that is trange.
« Reply #3 on: 06/28/2017 01:44 PM »
There can be multiple planets transiting the star (even without a Laplace resonance). However, since all planets have different distances from their star, they also have different periods, so while they would occasionally block the light of the star "together", most of the time, they would not, and just transit individually. By looking at many transits spread over multiple orbits, the orbits (and radii) of the individual planets can be disentangled.

#### jebbo

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##### Re: I think that i found something in the kepler mission that is trange.
« Reply #4 on: 06/28/2017 01:59 PM »
There can be multiple planets transiting the star (even without a Laplace resonance). However, since all planets have different distances from their star, they also have different periods, so while they would occasionally block the light of the star "together", most of the time, they would not, and just transit individually. By looking at many transits spread over multiple orbits, the orbits (and radii) of the individual planets can be disentangled.

Doh, indeed!  The reason I mentioned Laplace resonances is that this is the most difficult case as the transits always line up and (assuming identical radius), the only way of noticing it is the transit durations ...

My brain skipped over the simple cases :-)

--- Tony

#### Hungry4info3

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##### Re: I think that i found something in the kepler mission that is trange.
« Reply #5 on: 06/28/2017 03:55 PM »
It's also worth noting that transit duration is not simply a function of the orbital period, but also the impact parameter. A longer-period planet can have a shorter transit duration than a shorter-period planet.

Tags: kepler