A 3rd planet around Kepler-47

[ProtoJeb21]

Kepler-47, the first (and so far only) multi-planet circumbinary system around two main-sequence stars, just got a whole lot more interesting with the confirmation of a much larger third planet. 

https://www.space.com/amp/third-alien-planet-in-tatooine-system-kepler-47.html

The new planet, Kepler-47d, is roughly 7 Earth radii and orbits every 187.4 days in the inner portion of the system’s habitable zone. That makes Kepler-47 the only system with TWO circumbinary habitable zone planets, a title that is probably going to be hard to beat. However, before anyone gets excited about potentially habitable exomoons, it should be noted that all three planets are extremely puffy — Kepler-47c could only be 3-5 times the mass of Earth despite being bigger than Neptune — so they probably aren’t massive enough to form or capture moons large enough to hold a significant atmosphere. 

[ILoveStars]

With the addition of Kepler-47 d, will the system be stable? Because for me, it doesn't look really stable.

[ProtoJeb21]

6 hours ago, ILoveStars said:

With the addition of Kepler-47 d, will the system be stable? Because for me, it doesn't look really stable.

The discovery team ran some simulations and found that it is stable for at least 100 million years, and since the system is already 3.5 billion years old, it’ll be stable for even longer. 

[ILoveStars]

On 4/17/2019 at 12:13 PM, ProtoJeb21 said:

The discovery team ran some simulations and found that it is stable for at least 100 million years, and since the system is already 3.5 billion years old, it’ll be stable for even longer. 

Are the planets in resonances? Well, it looks to me like b and d are in a 2:1 resonance, but I don't know about c.

[Hypercosmic]

On 4/23/2019 at 4:37 PM, ILoveStars said:

Are the planets in resonances? Well, it looks to me like b and d are in a 2:1 resonance, but I don't know about c.

https://en.wikipedia.org/wiki/Kepler-47

b: 49.51 days

d: 187.35 days

c: 303.158 days

...they're close, but probably not close enough.

[ILoveStars]

6 hours ago, Hypercosmic said:

https://en.wikipedia.org/wiki/Kepler-47

b: 49.51 days

d: 187.35 days

c: 303.158 days

...they're close, but probably not close enough.

 

30:8:5?

Edited April 25, 2019 by ILoveStars

[Hypercosmic]

 

 

 

25 minutes ago, ILoveStars said:

30:8:5?

...so 15:4 for 47b and 47d, and 8:5 for 47d and 47c?

The former is within 1%, and the latter is within 1.2%, apparently. Not bad.

[ILoveStars]

what, my calcs?

[Hypercosmic]

10 hours ago, ILoveStars said:

what, my calcs?

Nope, I wasn't talking about your calcs, but you're pretty good with numbers. I guess I need to look into these kinds of stuff more...