Astronomers discover 28 new exoplanets

Astronomers have discovered 28 new planets outside of our solar system, increasing to 236 the number of known exoplanets.

"We added 12 per cent to the total in the last year, and we’re very proud of that. This provides new planetary systems so that we can study their properties as an ensemble," said Jason Wright of the University of California at Berkeley, one of the study team members. Wright said the planets are among the 37 new objects spotted within the past year.

Seven of the objects are failed stars called brown dwarfs, having masses that dwarf the largest, Jupiter-sized planets. But they are too small to sustain the nuclear reactions necessary for stellar ignition, he said.

According to Wright, at least four of the newly spotted planets belong to multiple-planet systems, supporting the idea that at least 30 percent of all planet-parent stars have more than one planetary companion.

"Since smaller planets and those outside our solar system are trickier to detect, this percentage will continue to rise as detection methods improve," said Wright, adding that three of the just-discovered planets circle stars that boast masses between 1.6 and 1.9 times that of our Sun.

He further said the stars are of the A- and F-types, which are typically difficult to detect because they rotate fast and have pulsating atmospheres.

Due to their extreme rotational velocities and high temperatures, A and F stars only jitter slightly from orbiting planets and so surveys can only pick up wobbles from super-massive planets and brown dwarfs in short-period orbits around these stars, said Wright. — ANI