Nearby star hosts closest alien planet in the 'habitable zone'
Nearby star hosts closest alien planet in the 'habitable zone'December 16, 2015
UNSW Australia astronomers have discovered the closest potentially habitable planet found outside our solar system so far, orbiting a star just 14 light years away.
The planet, more than four times the mass of the Earth, is one of three that the team detected around a red dwarf star called Wolf 1061.
"It is a particularly exciting find because all three planets are of low enough mass to be potentially rocky and have a solid surface, and the middle planet, Wolf 1061c, sits within the 'Goldilocks' zone where it might be possible for liquid water—and maybe even life—to exist," says lead study author UNSW's Dr Duncan Wright.
"It is fascinating to look out at the vastness of space and think a star so very close to us—a near neighbour—could host a habitable planet.
Read more at: http://phys.org/news/2015-12-nearby-star-hosts-closest-alien.html#jCp
Add wolf 1061c to the growing list of earth/super earth habitual planets. This and G667cc are currently the two closes confirmed such planets.
If we really needed to get off this planet fast...Well, this would be a option.
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Gravity is proportional to mass, but inversely proportional to the radius-squared. So size is more important than mass.
We need to know either this planet's size or its density, which will give us its size.
Then, we will know its surface gravity.
At 5.21 times Earth mass, it would only have to have a radius of about 2.3 times that of the Earth to have the exact same gravity as the Earth. That is how the math works out.
First, Wolf 1061 is a red dwarf, type M3, which means it is a dim, cool star. Any planet in the habitable zone is going to be close in. And indeed, Wolf 1061c has an orbital period of about 67 days. This could mean that the planet may be tidally locked to its star, with one side perpetually facing the star as it orbits. I am not sure if this is the case, but it needs to be considered.
Second, this is a super-Earth, over five times Earth's mass. Now that does not mean five times the gravity, because gravity also depends on size. However, that's pretty damned massive for a terrestrial-type planet. It is likely that it is a rocky planet, but we just do not yet know.
Those are the kinds of questions I would be asking.
We need to know the planet's size/density, which will give us its gravity, and whether it could be tidally locked to its star.
R&K
The three newly detected planets orbit the small, relatively cool and stable star about every 5, 18 and 67 days. Their masses are at least 1.4, 4.3 and 5.2 times that of Earth, respectively.
https://www.science.unsw.edu.au/news/discovery-nearby-star-hosts-closest-alien-planet-in-habitable-zone
We've found quite a few planets with masses that are 4 all the way up to 10+ times the mass of our planet that turned out rocky. Kepler 10c is such a planet.
We'll just have to wait and see. 
While the press release asserts the planet is likely rocky, I'm not so sure. There's a couple objections I have:
1) While we're still populating the Mass-Radius parameter space, several of the planets that are several times the mass of Earth are turning out to be low-density, puffy "mini-Neptune"-type planets. See [url=
]this Mass-Radius diagram[/url] for example.
2) The method that detected the planets at Wolf 1061 does not provide us with the true masses of its planets, but rather the minimum mass. The true mass of the planet depends on the inclination of the planet's orbital plane against the plane of the sky, such that an edge-on orbit is 90 degrees, and an orbit that we're viewing face-on would be 0 degrees. The true mass of the planet is equal to the derived minimum mass (which is the value quoted by this research) divided by the sine of the inclination (which is why planets detected through this method have masses that are talked about in terms of mp sin i, with mp being the unknown true mass). Since the true mass of the planet is almost certainly higher, this pushes it further toward the mini-Neptune class of planets that would rule out habitability.
So in summary, don't hold your breath for this one.
