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View Full Version : One planet orbiting two stars. Will it work that way? Perhaps? Maybe?



potoole
2012-Sep-07, 08:18 PM
Kepler discovers planetary system orbiting 2 sunsWednesday, August 29, 2012
( http://www.labspaces.net/123046/Kepler_discovers_planetary_system_orbiting___suns )

The system, known as Kepler-47, contains a pair of stars whirling around each other every 7.5 days. One star is similar to the Sun while the other is a diminutive star only one third the size and 175 times fainter. The inner planet is only 3x larger in diameter than the Earth, making it the smallest known transiting circumbinary planet. It orbits the stellar pair every 49 days.

Are they saying that the planet is orbiting both stars, with both stars centrally located, not just one of them ?

Noclevername
2012-Sep-07, 08:37 PM
The system, known as Kepler-47, contains a pair of stars whirling around each other every 7.5 days. ... It orbits the stellar pair every 49 days.

Are they saying that the planet is orbiting both stars, with both stars centrally located, not just one of them ?

It's orbiting the barycenter, which given the sizes and distances quoted is probably not below the surface of the larger star, I think.

potoole
2012-Sep-07, 11:45 PM
It's orbiting the barycenter, which given the sizes and distances quoted is probably not below the surface of the larger star, I think.

So, the 3x earth size planet gets energy from both stars, am I correct?

Would it be possible to determine a goldilocks zone of this star system?

Hornblower
2012-Sep-08, 12:07 AM
So, the 3x earth size planet gets energy from both stars, am I correct?

Would it be possible to determine a goldilocks zone of this star system?

According to the article, the larger, outer planet is in that zone. The inner one is closer in than Mercury is to the Sun, so it would be too hot.

In general, a coplanar orbit at several times the separation of the stars will be stable, with only a small ripple effect in the gravitational field to distinguish it from an orbit around a single star of the same total mass.

potoole
2012-Sep-08, 12:58 AM
If there is a large Uranus sized planet in the goldilocks zone, would that prevent a smaller, earth sized, planet from occuring in the zone?

Noclevername
2012-Sep-08, 01:06 AM
If there is a large Uranus sized planet in the goldilocks zone, would that prevent a smaller, earth sized, planet from occuring in the zone?

Maybe there could be a large moon of that giant.

potoole
2012-Sep-08, 02:57 AM
Maybe there could be a large moon of that giant.

Very interesting, thank you.