“We have estimated that the mean temperature of this super-Earth lies between 0 and 40 degrees Celsius, and water would thus be liquid,” said Stéphane Udry from the Geneva Observatory, Switzerland and lead-author of the paper in the journal Astronomy and Astrophysics. It is orbiting its host star (red dwarf) already known to astronomers to harbor two other planets of which one is of a Neptune-mass planet.

This red dwarf star known as Gliese 581, is colder, smaller and much less luminous than our Sun. Gliese 581 is one of 100 closest stars to us and its location was determined to be 20.5 light-years away in the constellation Libra (“the Scales”).
The star's mass is approximately one third that of the Sun. This is the most common type of red dwarfs stars in the Milky Way.

“Red dwarfs are ideal targets for the search for such planets because they emit less light, and the habitable zone is thus much closer to them than it is around the Sun. Any planets that lie in this zone are more easily detected with the radial-velocity method, the most successful in detecting exoplanets,” said Xavier Bonfils, a co-worker from the Center of Astronomy and Astrophysics of the University of Lisbon, Portugal.

It is too early to say in what degree the found planet resembles our own planet. For the time being the scientists of the European Southern Observatory (ESO determined that unlike our Earth, this planet takes only 13 days to complete one orbit round its star. Additionally, it is also 14 times closer to its host star than the Earth is from the Sun.

The new discovered so called "exoplanet" (exoplanets are orbiting stars oth­er than our Sun) is located in so called "habitable zone". In "our" habitable zone we need liquid water in order to survive.
“Liquid water is critical to life as we know it and because of its temperature and relative proximity, this planet will most probably be a very important target of the future space missions dedicated to the search for extra-terrestrial life. On the treasure map of the Universe, one would be tempted to mark this planet with an X,” added Xavier Delfosse, a member of the team from Grenoble University in France.
Two years ago, Stephane Udry and his team of the Geneva Observatory, Switzerland, discovered another planet orbiting around Gliese 581 in 5.4 days, which has mass as much as 15 Earths.

Many scientists support the concept of red dwarfs planets as habitable zones but still many necessary calculations have yet to be made in order to determine whether red dwarf stars can support life (as we know it) on surrounding them, planets.
In 1997, Martin Heath of Greenwich Community College in London, suggested that if the ocean basins are deep enough, water will circulate back from the dark and cold side to the hot. Under a deep ice cap, sea water would be protected from the extreme cold and remain liquid and thus be able to freely disperse. From our, humans' point of view, very specific conditions appear to be necessary for existing of life similar to that on Earth. We depend much on water and our life most probably started in the sea.

Therefore, we must seek out planets with liquid surface water and a climate stable enough for life to develop. Each candidate cannot be so small that it is not able to retain atmosphere nor so large that it is like Jupiter. Habitable zones have two parameters. The first one is their distance from their parent star and the second is their duration. The spectral type of the parent star determines these parameters. The spectral type is based primarily on a temperature sequence.

In other words, the temperature decides the distance of the habitable zone from the central star. If a star is very hot, the habitable zone will be further away, and naturally, the other way around, when a star is colder, the habitable zone is closer.

Thus, our planet is the only located within the Sun’s habitable zone. We are lucky indeed.
Most scientists believe it is in these habitable zones that we may alien life.