Scientists say they have discovered 50 new exoplanets orbiting nearby stars to include 16 super-Earths, making it the largest number of such planets ever announced at one time.

The HARPS team, led by Michel Mayor of University of Geneva, Switzerland, made the discovery and presented the findings at a conference on Extreme Solar Systems. The conference brought together 350 exoplanet experts who met in Wyoming.

"The harvest of discoveries from HARPS has exceeded all expectations and includes an exceptionally rich population of super-Earths and Neptune-type planets hosted by stars very similar to our Sun," Mayor says in a press release. "And even better - the new results show that the pace of discovery is accelerating."

The HARPS spectrograph on the 3.6-metre telescope at ESO's La Silla Observatory in Chile is the world's most successful planet finder as it measures the radial velocity of a star with extraordinary precision.

A planet in orbit around a star causes the star to regularly move towards and away from a distant observer on Earth. And because of the Doppler effect, this radial velocity change induces a shift of the star's spectrum towards longer wavelengths as it moves away - redshift ‑ and a blueshift (towards shorter wavelengths) as it approaches.

HARPS measures this tiny shift of the star's spectrum and it is used to infer the presence of a planet.

In the eight years since it started surveying stars like the Sun using the radial velocity technique, HARPS has been used to discover more than 150 new planets.

About two thirds of all the known exoplanets with masses less than that of Neptune were discovered by HARPS. These results took several hundred nights of HARPS observations.

Scientists will be pushing HARPS to the next level of stability and sensitivity to search for rocky planets that could support life by upgrading both hardware and software systems. They say 10 nearby stars similar to the Sun were selected for a new survey. These stars had already been observed by HARPS and are known to be suitable for extremely precise radial velocity measurements.

After two years of work, the team of astronomers has discovered five new planets with masses less than five times that of Earth.

"These planets will be among the best targets for future space telescopes to look for signs of life in the planet's atmosphere by looking for chemical signatures such as evidence of oxygen," says Francesco Pepe of Geneva Observatory, Switzerland, in a statement. He is the lead author of one of the recent papers on the discovery.

One of the newly discovered planets is HD 85512 b.

It is estimated to be only 3.6 times the mass of the Earth and is located at the edge of the habitable zone. This is a narrow zone around a star in which water may be present in liquid form if conditions are right.

"This is the lowest-mass confirmed planet discovered by the radial velocity method that potentially lies in the habitable zone of its star, and the second low-mass planet discovered by HARPS inside the habitable zone," says Lisa Kaltenegger of Max Planck Institute for Astronomy, Heidelberg, Germany, and Harvard Smithsonian Center for Astrophysics, Boston. She is an expert on the habitability of exoplanets.

Mayor says the detection of HD 85512 b is far from the limit of HARPS and "demonstrates the possibility of discovering other super-Earths in the habitable zones around stars similar to the Sun."

ok somebody help me out..what is a "super earth"?

cool I wonder which one I'm gonna rule?

Earth-like planet discovered in 'habitable' zone

Astronomers on Monday reported the discovery of an Earth-like planet outside the solar system whose size and distance from its own star put it in the "habitable" zone and make for a surface temperature perhaps averaging a balmy 72 degrees.

The planet, Kepler 22b, about 2.4 times wider than Earth, circles a star about 600 light years away, close by astronomical standards. The Kepler space telescope discovery team announced the find at a briefing at NASA's Ames Research Center in Moffett Field, Calif.

"It is right smack in the middle of the habitable zone," Kepler scientist Natalie Batalha says. Launched in 2009, the $591 million Kepler space telescope has detected more than 2,000 possible planets observed among about 150,000 stars within 3,000 light years of Earth along the "Orion spur" of our Milky Way galaxy. Kepler 22b's discovery caps a half-decade of astronomers searching for a "Goldilocks" planet — not too hot or not too cold to harbor oceans on its surface, like Earth. Liquid water is considered key for development of life.

"This is a phenomenal discovery in the course of human history," says planet hunting pioneer Geoff Marcy of the University of California-Berkeley, a Kepler investigator. European astronomers discovered the first planet confirmed orbiting a nearby star in 1995, spurring a gold rush of planet discoveries, mostly jumbo planets the size of Jupiter or larger.

Kepler 22b "is the smallest, most nearly Earth-size, planet ever found in the lukewarm zone around another sun where life could thrive."

Kepler spotted the planet from tiny dips in starlight caused by partial eclipses, or transits, of the planet in front of the star. It travels on a 290-day orbit around a sun-like star, dubbed Kepler 22a, nearly as bright and warm as our own. Astronomer Francesco Pepe of Switzerland's University of Geneva, says he is "convinced that the report will be solid and the data impressive" from the Kepler 22b discovery. Pepe is a member of a competing European Southern Observatory planet-hunting team that announced an Earth-sized planet on the edge of another star's habitable zone in September.

The transit detection method yields only a width and orbit time for planets, instead of a weight. Preliminary telescope observation of the planet's star for gravitational wobbles induced on it by the planet indicate only that Kepler 22b cannot weigh more than 36 times more than Earth.

"There is absolutely no doubt about the reality of this planet," Marcy says, given that the Kepler team has detected three 7.9-hour dimmings of the star, reoccurring at 290-day crossings in front of the star.

"This discovery is rock solid, even if the planet isn't," Marcy says.

From early observations, the Kepler astronomers cannot tell whether Kepler 22b is a rocky world, a water-covered world or something else, says team leader William Borucki of NASA's Ames Research Center. Borucki says observations show no signs of other planets in the star's solar system. Pepe estimates that the world would weigh about 14 times as much as Earth if it is built the same way.

Most likely, Marcy says, "this planet is probably rocky with a thick layer of water and gas, making it more like Neptune in our solar system."

Among the more than 2,000 possible planets spotted by Kepler are 10 planets less than 2.4 times as wide as Earth that linger in the ocean-friendly "habitable zone" distances from their stars, awaiting confirmation. "(W)e Homo sapiens are straining our reach into the universe to find planets that remind us of home," Marcy says by e-mail. "We are almost there."