Would this gas giant also put out deadly radiation like Jupiter?

Well given the size it is more likely a high-Z (metal-rich, which refers to elements other than hydrogen and helium) planet more like Uranus and Neptune than Jupiter. I use the term “high-Z” rather than the common “ice giant” because the Kepler-47 planets have migrated through the inner system where they may well have picked up substantial amounts of rocky (as opposed to icy) material, and also we don’t actually know how much ice is in Uranus and Neptune anyway (there could be a lot of rock there as well). Uranus and Neptune have weird magnetic fields, the magnetic axis is substantially offset from the centre of the planet – it looks like the magnetic fields are generated in a fluid layer nearer the “surface” of the planet than the centre. They do maintain radiation belts nevertheless.

We actually know frustratingly little about the structure of Uranus and Neptune, let alone extrasolar Neptune-mass planets. It seems likely that there are significant differences between the two (so much for them being “twin planets”). In particular, Uranus appears to lack an internal heat source so heat from the Sun plays a significant role in its energy budget, while Neptune does exhibit internal heating. We also don’t know if these planets have a well-defined separation between the core, the mantle and the outer atmosphere.

In short, we need another mission to both these planets, preferably with orbiters. Uranus itself seems to have a bit of a reputation for being a bland target and the moons so far appear to lack the cryovolcanic activity seen elsewhere. On the other hand, Hubble reveals significant seasonal variations and the inner moons and ring system seems to be a highly dynamic environment with rings forming and disappearing on timescales of years. Furthermore several of the shepherd satellites have unstable orbits.

And finally, the stupid joke is stupid.

BTW, I gather Venus probably lost an ocean or manys worth of water which would once have absorbed a lot of carbon dioxide before the Cytherean oceans boiled and steamed and photodissociated away.

@33. amphiox :

If these two stars merged, would the result be a Sirian type star? The smaller star is 1/3 the sun’s mass, and the larger one is about the same as the sun’s, so the merger would at most produce a star about 1 1/3 the sun’s mass, while Sirius has twice the sun’s mass.
(IE, wouldn’t the product of the merger still be a G or maybe F class star?)

Yes, for *this* system the result of a stellar merger would be, I think, an early G or late F type dwarf star given those respective masses.

The system I was imagining there was ER Vulpeculae which consists of two solar twins so would produce a Sirian type star. Sorry, if that wasn’t clear.

@39. Gunnar :

Have you read Robert L. Forward’s Saturn Rukh?

No I hadn’t heard of that one before. Cheers – will have to see if I can find a copy.

So if we invent FTL travel to go check it out, I’ll bet you a thousand to one that it doesn’t have sunny beaches and billion year old liquid water oceans.

Yet there’s been interesting speculations from many science fiction writers already about life inside gas giants such as Jupiter – Arthur C. Clarke in the Space Odyssey series and Ben Bova’s Jupiter novel in his Grand Tour series (click on my name for wiki-link) for instance.

Thanks for that tip! I have placed Bova’s Jupiter on my must read list. Have you read Robert L. Forward’s Saturn Rukh? It is about 5 explorers who descend into Saturn’s atmosphere and crash land on the back of a rukh, an enormous, sentient, flying creature that becomes aware of them and befriends them. It lived at a depth in Saturn’s Atmosphere where the pressure and density were just enough to buoy up its enormous mass, and the temperature permitted the existence of liquid water. I think you would enjoy it. I certainly did!