Scientists discover a giant planet that orbits two suns – and could have habitab

[Eugene]

Source: Washington Post

Scientists discover a giant planet that orbits two suns – and could have habitable moons

By Rachel Feltman June 13 at 1:00 PM

Some worlds have more than one sun in their sky. Now scientists say they've confirmed the existence of the largest-ever planet orbiting a pair of binary stars – a gas giant with the same mass and radius as Jupiter. Exoplanets like this one – situated in their stars' habitable zone and massive enough to lasso in many rocky moons – could be an interesting place to go looking for signs of alien life.

The newly confirmed behemoth has been dubbed Kepler-1647 b, and it sits 3,700 light-years away in the constellation Cygnus. At an estimated 4.4 billion years old, it's roughly the same age as Earth. But it's nothing like our home planet. It's what is known as a circumbinary world – one that orbits two suns that dance together as a binary pair – and it's the size of Jupiter, a planet with a diameter more than 11 times that of Earth's. Its suns are pretty similar to our own (one is slightly smaller and the other slightly larger) but, well, there are two of them.

At about 2.7 astronomical units (AUs) from its suns (Earth is 1 AU from ours) Kepler-1647 b is in the habitable zone of its stars. That means it's in the magic sweet spot that experiences the right amount of sunlight and heat to allow liquid water to form. But the planet itself wouldn't actually be home to life as we know it: It's almost entirely made of gas. If it's anything like the gas giants in our solar system, however, it likely has dozens of moons – and just like the moons that orbit Saturn and Jupiter, those little rocky worlds could be great places to look for life like ours.

Scientists find exoplanets by measuring the way the light of their host stars dim when the planets "transit," or pass in front of the stars from our perspective. This is way harder to do with circumbinary planets, or CBP.

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Read more: https://www.washingtonpost.com/news/speaking-of-science/wp/2016/06/13/scientists-discover-a-giant-planet-that-orbits-two-suns-and-could-have-habitable-moons/


[font size=1]An artist's impression of the simultaneous stellar eclipse and planetary transit events on Kepler-1647 b. Such a double eclipse event is known as a syzygy. (Lynette Cook)[/font]

[bigdarryl]

1. A planet that far out these do called experts have no idea

If its a gas planet or not.

[longship]

3. Gas giants are about large mass. Right?

I think any Jupiter mass planet pretty much has to be a gas giant.

[getting old in mke]

4. Actually, they do.

Since it is a transiting planet and they've now observed two passes, they not only get the size but also can use spectragraphic tools to observe the changes to the stars standard emissions when the planet is in transit. The difference between the before and during spectra allows them to calculate what the composition of the gaseous parts of the planet.

Other exoplanet detection methods don't make the composition detection so easy.

[leveymg]

2. Sounds like the basis for Avatar. Looks better in color>