Ah—it's really Class M, after all?

(And no, this image is NOT an HD framegrab from the early seconds of the opening title of the newly remastered The Next Generation:)

In the second follow-up after its discovery in September 2010:

"Gliese 581g Exoplanet May Be 'Potentially Habitable' Alien World After All"

By: Mike Wall
Published: 07/23/2012 04:08 PM EDT on SPACE.com

... The ... planet was said to orbit in the middle of its star's "habitable zone" — that just-right range of distances where liquid water, and perhaps life as we know it, could exist.

Just a few weeks later, however, another prominent research team began casting doubt on the find, saying the alien planet didn't show up in their observations. ...

But in a new study that will be published Aug. 1, 581g's discoverers examine the Swiss team's since-expanded data set and take issue with their conclusions, saying that the evidence supports the planet's existence after all. ...

...

"The take-away message is, regardless of who eventually gets bragging rights to the discovery of the first truly confirmed habitable Earth-sized planet, we are starting to find them in unexpected numbers, and unexpectedly nearby," Vogt said. "That means there are many, many out there, at least tens of billions or more, in our own galaxy alone."