Scientists, using the Kepler space telescope have discovered six new planets orbiting a sun-like star, reports National Geographic.
The small planets are being dubbed "mini-Neptunes." Five of the six are closer to their sun than Mercury is to ours, and the sixth is farther out.
"This is the most closely packed known planetary system," said study co-author Jonathan Fortney, an astronomer with the Lick Observatory at the University of California, Santa Cruz.
Scientists say the planets are roughly 2 to 4.5 times the size of Earth, but seem to be extremely lightweight, suggesting they are made mostly of gases.
Two planets may have atmospheres of water, hydrogen and helium.
In finding a cluster of planets like this, scientists can get a better idea of planetary transformations.
"We can do comparative science and ... we can think about how the evolution of the planets has diverged over time," Fortney said.
