UKC

http://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-34712877

'Clouds made from droplets of molten iron'- may give it a miss...

But how can the cloud temperature be 800c, if its the size of Jupiter- what could be its heat source?

And- the 'telescope in chile' shows multiple layers of thick and thin clouds- how can they tell- at 75 light years they can't resolve surface detail on a Jupiter sized object, surely..?

Cheers
Gregor

In reply to no_more_scotch_eggs:




I'm guessing that it's quite close to its sun(s)?

In reply to JJL:

It doesn't have one- that's the story- its 'free floating'...

In reply to no_more_scotch_eggs:

oh. Ok. My bad. Doesn't that make it a meteor rather than a planet? I thought Planets (and asteroids) had to orbit something?

Otherwise, magnetic flux?

In reply to JJL:

Dunno. The astronomers who found it call it a planet, so I guess it is.

But it is odd- how would it form? I thought they formed out of the disc of matter circling a star- would this one have formed like that, then been ejected from its system? Or are there other ways to make a planet?

Perhaps it was the magratheans. Though clouds of molten iron seem pretty exotic even for the most eccentric of their clients...

In reply to no_more_scotch_eggs:

Calling Coel Hellier!

In reply to no_more_scotch_eggs:

I'm guessing the atomic rooster's nest has fallen into the soup dragon's stove. Shame.

In reply to no_more_scotch_eggs:


Interestingly the actual paper makes no mention of "molten iron", and I've no idea how such a thing would be detected anyhow. So, whoever wrote this press release seems to have embellished that bit.


The heat source would be contraction under gravity.


You're right, they can't. What they did is observe the object to vary in intensity over time. They hypothesize that the object has patchy clouds, and that, as it rotates the patchy clouds cause the change in observed light.

They also model the spectrum, finding that a combination of two temperatures, 100 K different, ``marginally fit the spectrum better than a single component fit''. Hence different cloud layers at different temperatures.

Overall, the press release seems rather ``inventive''.

In reply to Coel Hellier:

Ok thanks coel, it did seem a remarkable amount of detail.

Re the heat source being from contraction under gravity- if its the size of Jupiter, why is Jupiter not that hot then?

Or is it actually considerably more massive?

And what about its origin - does the paper comment on that- is it likely to have been ejected from a more standard solar system?

In reply to no_more_scotch_eggs:


This object is much younger, in a recently formed cluster of stars about 20 million years old. So it will still be cooling, radiating away the energy of the gravitational contraction from the gas cloud it formed out of. Jupiter is of course 4.5 billion years old, so has had vastly more time to cool.


Yes, quite likely. It's part of a 20-million-yr-old cluster, so likely it formed around a star in the usual way, and then got ejected owing to gravitational interactions with other stars, causing it to get ejected from its solar system.

Having said that, it's conceivable it might have formed out of a gas cloud in such a way that it wasn't gravitationally bound to any star in the first place.

The paper here for anyone interested: http://adsabs.harvard.edu/abs/2015arXiv151007625B

In reply to no_more_scotch_eggs:

That picture is photoshopped

In reply to Coel Hellier:

That makes sense. 'Lone planet' formation sounds interesting- i didn't realise that was possible. Could there be lots of them out there then? They'd be hard to spot unless you were specifically looking for them, and even then would take some spotting I'd have thought...

In reply to no_more_scotch_eggs:


A lone planet made of iron heading for our solar system smacks of the Dr Who plot for Tenth Planet. Beware the Cybermen.

In reply to no_more_scotch_eggs:

The fact of it being on it's own doesn't seem all that strange. More than likely it was part of a standard stellar system and then got knocked out by the gravitational influence of a passing star, or even by other planets in it's system. There's no such thing as a stable planetary system once you've got two or more planets. The Solar System is chaotic over very long timescales, and there's nothing to say that in a billion years the Earth might not be hurtling towards Alpha Centauri.

The fact that they were able to spot it blows my mind.

In reply to Coel Hellier:

why not a brown dwarf?