Aug 24, 2010 10:47 GMT  ·  By
This artist’s impression shows the remarkable planetary system around the Sun-like star HD 10180
   This artist’s impression shows the remarkable planetary system around the Sun-like star HD 10180

Astronomers with the European Southern Observatory (ESO) managed to discover the most populated solar system known. The research team used a highly advanced instrument for the job.

Over the past few couple of decades, researchers brought the number of discovered exoplanets to more than 450, but they never discovered “foreign” solar systems that could rival the size of our own.

In order to conduct the new observations, researchers traveled to La Silla, Chile, where the ESO 3.6-meter telescope is installed.

The group used the HARPS spectrograph attached on the observatory. This tool can take measurements of unrivaled precision and stability, which is why it was used in the first place.

It was pointed at the Sun-like star HD 10180, which resides fairly close-by, at just 127 light-years away from Earth. Amateur astronomers can find it in the southern constellation of Hydrus.

The star is host to a planetary system featuring at least five planets, although experts at ESO believe that another two celestial bodies may be circling it.

At this point, the discovery has yet to be confirmed, but ESO experts say that one of the two bodies has the lowest mass ever discovered in an exoplanet ever.

Another reason why the discovery stands out is the fact that, if the two new planets turn out to actually exist, then the HD 10180 system will be the second-largest known, featuring 7 members.

For comparison, our system contains 8 established planets, plus a number of dwarf planets, orbiting the Sun in the inner asteroid belt and beyond the orbit of Pluto, respectively.

“We have found what is most likely the system with the most planets yet discovered. This remarkable discovery also highlights the fact that we are now entering a new era in exoplanet research: the study of complex planetary systems and not just of individual planets,” says Christophe Lovis.

“Studies of planetary motions in the new system reveal complex gravitational interactions between the planets and give us insights into the long-term evolution of the system,” adds the expert, who is also the lead author of a new scientific paper detailing the findings.

“We also have good reasons to believe that two other planets are present,” he adds.

According to calculations, one would orbit the star in 2,200 days, and would feature a mass 65 times heavier than that of Earth. In other words, it would be a Saturn-like giant.

The second planet is just 1.4 times heavier than Earth, which makes the lightest exoplanet ever found. It orbit HD10180 at very close range. A year there lasts only 1.18 Earth days.

The new paper, called “The HARPS search for southern extra-solar planets. XXVII. Up to seven planets orbiting HD 10180: probing the architecture of low-mass planetary systems,” was submitted for publication to the esteemed journal Astronomy and Astrophysics.