Astronomers have discovered 60 new planets beyond our solar system.

The international team, which includes Dr Mikko Tuomi from the University of Hertfordshire, found the new extrasolar planets orbiting stars close to Earth’s solar system.

The scientists also found evidence of a further 54 planets, bringing the potential discovery of new worlds to 114.

The team said the planets are in our “immediate solar system” and one in particular, Gliese 411b, is of particular interest.

Gliese 411b is a hot super-Earth with a rocky surface located in the fourth nearest star system to the Sun, making it the third nearest planetary system to the Sun.

The significance of its discovery demonstrates that virtually all the nearest stars to the Sun have planets orbiting them – planets like Earth.

The results, which are part of the Lick-Carnegie Exoplanet Survey, are based on observations taken over a 20-year period by American astronomers using the Keck-I telescope in Hawaii.

During that time, the team obtained almost 61,000 individual observations of 1,600 stars.

Dr Tuomi, who was the only European-based researcher working on the project, led the group's data analysis efforts that revealed the existence of the newly reported planets.

Dr Tuomi said: “It is fascinating to think that when we look at the nearest stars, all of them appear to have planets orbiting them.

“This is something astronomers were not convinced about, even as little as five years ago.

“These new planets also help us better understand the formation processes of planetary systems and provide interesting targets for future efforts to image the planets directly.”

The Lick-Carnegie Exoplanet Survey was started in 1996 by astronomers Steve Vogt and Geoffrey Marcy from the University of California, and Paul Butler from the Carnegie Institute of Science, in Washington.

Dr Butler said: "This paper and data release is one of my crowning achievements as an astronomer. 

"It represents a good chunk of my life’s work."

For over two decades, the Lick-Carnegie survey has steadily increased scientists’ understanding of planets beyond the solar system by enabling them to study the tiny wobbles of nearby stars, caused by orbiting planets.

Dr Tuomi said: “Keck-I telescope and its instruments have been wonderful tools in establishing the current consensus that virtually all stars have planets orbiting them.

“These new discoveries will further help us characterise the population of planets in the immediate solar neighbourhood.’"

The group's results were based on measuring small periodic changes in the target stars' colours, indirectly revealing the existences of the planets.

They detected the signatures of planets using the iodine cell radial velocity technique, which superimposes spectral lines from an iodine gaseous absorption cell onto the stellar absorption lines.

While the lines of the star move very slightly in response to orbiting bodies like planets, the iodine lines do not move, providing a precise reference point.