The discovery, to which several national and foreign researchers from the Institute of Astrophysics and Space Sciences (IA) in Portugal contributed to, is described in an article published today in the specialist journal of Astronomy & Astrophysics.

The planetary system in question is 35 light-years from Earth, possibly made up of five planets (the fifth planet is doubtful) that orbit the star L 98-59 and was observed with a spectrograph of the VLT telescope, operated in Chile by the OES, an organisation which Portugal is part of.

According to astronomers, three of the extrasolar planets are rocky and may contain water in their interior or atmospheres: the two planets closest to the star are likely dry but may have small amounts of water, while the third may have up to 30 percent of its mass formed by water. The team suspects that there is a fifth planet in the so-called "habitable zone", at a distance from the star that allows it to have liquid water on its surface (an essential condition for life as is known).

"The planet in the habitable zone may have an atmosphere that could protect and sustain life," said astronomer María Rosa Zapatero Osorio, from the Center for Astrobiology in Madrid, Spain, in a statement quoted by OES. "We are finally getting closer to detecting a terrestrial planet in the habitable zone of its star, from which we will be able to study the atmosphere," said the first author of the article, Olivier Demangeon, researcher, quoted in the same statement.