Lazy, Lazy, Lazy

I can’t believe how lazy I am sometimes … I’ve just realised I’ve not uploaded any of these before!!

The Last Tree

This piece (larger version here) was done for a contest on dA. Unsurprisingly enough, it didn’t win, but it was still fun. The theme of the contest was the end of the world. I got bored of all the generic, vaguely-Christian stuff that was getting knocked out, so I decided to apply astronomy to the brief. Here we have the Earth of 5 billion years hence. The Sun, as you can see, is now on the very cusp of red giant-hood. Silhouetted against it is the fossil remains of the last ever tree (which would actually have died millions of years previously). The reddish stuff in the sky is actually plasma ejected by the Sun – the Earth no longer has an atmosphere by this point.

Falling

Poor, poor ‘Falling’. No-one ever looks at you, and hardly anyone looks at the painting that you’re a panel from (‘Shadow of the Traitor’). Which is a real pity, as I all but busted a gut doing it. I mean, there’s even a face! (And it only gets as many views as it does because it’s a 40K piece, as well.)

And yes, the gas giant is actually a brown dwarf. Presumably it’s a very late-T, since only a few bits of it are visibly-glowing. Maybe T8 or T9?

Halo Brown Dwarf

And that brings me onto this piece, which is something I did for a talk a few weeks ago. It’s meant to represent the objects that I study – brown dwarfs in the galactic halo. This is a figurative depiction rather than a strictly-literal one – the Milky Way is rather brighter than it would actually look, for instance. However I wanted to try and get the idea of out-of-plane and highly-inclined orbits, which is kind of the whole point of the stellar halo. I also wanted to work the idea of its great age in there, but I wasn’t quite sure how. There’s a higher-res version over here.

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4 Responses to “Lazy, Lazy, Lazy”

  1. I like the way you’ve treated the bands in the brown dwarf on the middle picture. This is something that has been puzzling me, at some point between a gas giant and a small star the tendancy towards bands disappear and convection currents and granulation appear. So do brown dwarves have the tail end of bands? Do they have some convection currents? I’d loved to paint some pictures of them but I’d like to get it reasonably accurate

    • I’m glad you like it πŸ™‚

      Aaah, granulation and condensate formation! The short (and brutally honest) answer is, we don’t actually know.

      Brown dwarfs are expected to have weather, and there is some work going on with people trying to identify variability in their NIR magnitudes (the theory is, if it’s a cloudy day on the T-dwarf, it may get a bit fainter!). However, we would expect these things to be rotating, so I would expect there to be banded structure in the atmospheres as well as amorphous cloud.

      Also, different elements and chemicals have different vapourisation points, so as an object gets hotter it may well have clouds of different things. For instance, the coolest known T-dwarfs (T ~ 500 K, maybe even less) will possibly have a layer with water clouds. L dwarfs, however (T 1400 – 2200 K) are believed to have clouds of molten metal droplets(!). Cloud formation is thought to disappear (AFAIK) somewhere before you get to spectral class M, so early-L I guess.

      But the upshot is, you can certainly get away with painting banded brown dwarfs πŸ˜‰ And also, we’ll only know for certain when (if) someone ever manages to resolve a disk for a BD, and that is probably a long way off! So ATM, anything goes, really!

      • Thanks πŸ™‚ I’m going to have a think about this. So I take it that it’s very possible that a brown dwarf could have banding and be glowing very slightly.

      • Yes, banding is entirely possible. In fact, if I had to guess, I’d say probably fairly likely! And they will glow. An L dwarf will glow reasonably brightly – people have discovered loads of them in SDSS, despite it being an optical survey – and seen from nearby, a T dwarf will glow at least a bit. (You can see the glow on coals in a fireplace, and that’s the same sort of temperature range as T dwarfs.) If you have banding, it could get quite interesting, as different bands may be warmer and thus brighter than others. (That was partly what I was trying to get at in ‘Falling’.)

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