British scientists discovered a binary star system where it looks like the white dwarf star acted as a "cue ball," acting on the red dwarf and the two colored planets, like a game of Snooker.
Scientists originally thought the system NN Serpentis was just the two stars, the white dwarf and the red dwarf. But then scientists from the Universities of Warwick and Sheffield realized that there had to be at least two planets, due to the irregularities in the binary stars' orbits: a massive gas giant (six times the size of Jupiter) and a smaller gas giant (just 1.6 times Jupiter's mass.) Says Warwick physics professor Tom Marsh:
The two gas giants have different masses but they may actually be roughly the same size as each other, and in fact will also be roughly the same size as the red dwarf star they orbit. If they follow the patterns we see in our own star system of gas giants with a dominant yellow or blue colours, then it's hard to escape the image of this system as being like a giant snooker frame with a red ball, two coloured balls, and dwarf white cue ball.
And then they realized that at some point, the "cue ball" of the white dwarf had to have impacted these planets' orbits, in response to the other star becoming a red dwarf. Explains Sheffield university's Vik Dhillon:
If these planets were born along with their parent stars they would have had to survive a dramatic event a million years ago: when the original primary star bloated itself into a red giant, causing the secondary star to plunge down into the present very tight orbit, thereby casting off most of the original mass of the primary. Planetary orbits would have seen vast disturbances. Alternatively, the planets may have formed very recently from the cast off material. Either way, in relatively recent times in astronomical terms this system will have seen a vast shock to the orbits of the stars and planets, all initiated by what is now the white dwarf at the heart of the system.
Also involved in the discovery were scientists from Georg-August-Universitat in Gottingen, Germany, Eberhard-Karls-Universitat in Tubingen, Germany, Universidad de Valparaiso in Chile, and the University of Texas at Austin. [Aanda.org via Warwick University]