Hi All

Such a distant Jovian is hard to explain in current Solar Nebula theories. It's an anomaly that doesn't sit well with theorists.

In disk-instability theories a heavy disk can fragment into +20 protoplanets that then scatter gravitationally into high eccentricity orbits. No way of knowing how big GQ Lupi's original disk really was.

In Woolfson & Dormand's Capture theory Jeans-Mass condensations are typically captured into high eccentricity, high semi-major axis orbits. The star that captures them usually captures a disk of material that then circularises the protoplanets - which have condensed in a free-fall collapse to near-planet size, so they survive such resistence. Circularisation can reduce eccentricity and semi-major axis in typically ~ a few million years. Thus the proto-planet in the photo is still undergoing circularisation.

I say "usually" because the theory has been modelled and analysed statistically through a range of relative velocities, initial separations, mass differences and so forth. It's a theory that naturally produces diverse planetary systems, just like the ones observed over the last decade. Modelling of star formation during the high-density embedded phase in birth-nebula leads to anywhere from 6% - 25% of stars having planets, mostly by disrupted proto-brown dwarfs producing proto-planets through near misses with condensed higher-mass stars. Alternatively proto-planets can form out of Jeans-mass blobs formed during interactions between nebula disks, as can numerous brown-dwarfs. A lot of brown-dwarf formation studies produce "brown-dwarfs" through the interactions of higher-mass stars - and the multi-Jupiter mass exoplanets seen so far seem to blur the definition of just how big a planet gets before becoming a brown-dwarf.

Adam