5k Light Years Away Exists a System Much Like Our Own?

Scaled versions of Jupiter and Saturn orbiting a star 5000 light-years away, half as massive as the Sun, have been revealed from an effort involving a world-wide net of telescopes, including the UK's Liverpool Telescope on the Canary Islands. This marks the first discovery of another system of planets that has striking similarities with our Solar System. Moreover, it suggests that such giant planets do not favour the single-life but are more likely to be found in family groups. The research is published in the 15th February issue of Science.

Whilst there are more than 250 planets now known, there are only about 25 such systems with multiple planets and the newly discovered system resembles our own Solar System more closely than any previously observed.

Dr Martin Dominik, Royal Society University Research Fellow at the University of St Andrews, points out "Our gravitational microlensing technique is currently best suited for studying extra-solar planets that resemble the gas giants of the Solar System at their respective orbital radii, given that we do not need to wait for many years for them to complete their orbit."

The two newly discovered planets have revealed their existence through characteristic signatures in the received light during the gravitational microlensing event OGLE-2006-BLG-109. Rather than orbiting the observed star, these are associated with an unseen foreground star, systematically designated OGLE-2006-BLG-109L (where 'L' stands for 'lens), whose gravitational field (together with that of the planets) bent the light of the observed background star, with which it happened to be closely aligned.

While planet OGLE-2006-BLG-109Lb with 0.71 Jupiter masses is 2.3 times as far from its host star as the Earth is from the Sun, the less massive OGLE-2006-BLG-109Lc, 0.27 times the mass of Jupiter resides at twice the distance from its host star as its fellow companion.

Despite of the fact that their host star is only half as massive as the Sun, and therefore cooler, the OGLE-2006-BLG-109L planetary system otherwise bears a remarkable similarity to our Solar System. Both the ratio between the two masses of the detected giant planets (close to 3:1) and the ratio between their orbital radii (1:2) are remarkably similar to those of Jupiter and Saturn. Similarly, the ratio between the orbital periods of 5 years and 14 years, respectively, resembles that between Jupiter and Saturn (2:5).

Y'know, I have to wonder if a system like this one - and our own - requires a lower luminosity than is the norm for this to happen. hrm. This is onyl a 1/4 formed thought because I'm dealing with anthropocene T rexes and 'raptors again.