Nearby star hosts closest alien planet in the 'habitable zone'

Do you have any idea how hard even minimal activity would be at 4 Gs?

I'll wait until they can manage to find smaller planets or 1G +/- 0.2G moons around large planets.

ETA: woops, meant to reply to the OP.

Doesn't sound like much of a garden spot unless we manage antigravity units.

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.

That is Wolf 661D that is 5.21 times that of earth.

That would mean it would have 1G gravity at about twice Earth's radius.

However, with an orbital period of 17.87 days, this planet will undoubtedly be tidally locked to its star, which is a rather huge problem for life, and especially complex life, existing on it. At best, it would complicate things.

And what if it has rather high density and gravity? That would be another big issue.

However, I guess we just need to find out more about it. That's what the TMT will be for, if the ignorant assholes in Hawaii let it be built.

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.

https://en.wikipedia.org/wiki/Gliese_832_c 16 light years

https://en.wikipedia.org/wiki/Gliese_667_Cc 23 light years

If it is ever confirmed https://en.wikipedia.org/wiki/Tau_Ceti_e this one sits at 11.9 light years. Mostly likely very hot and very large...Of course, there's a few worlds that have been found to be of this radius to also be rocky. So who knows.

this is Tau ceti f...Which is also unconfirmed but it is smaller https://en.wikipedia.org/wiki/Tau_Ceti_f Since we don't know the radius of either wolf 6061c or this one. Well, it is hard to say.

Either way it is way to early to know for sure until we get the larger telescopes up, but it is quite exciting.

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 m[sub]p[/sub] sin i, with m[sub]p[/sub] 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.