Celestia Forums

I am wondering if is it any observation of a brown dwarf,because it seems that there is two opinions about it.Brown dwarfs are like jupiters that glow,or brown dwarfs are substars.This contrast in the two possible textures of browndwarf.jpg.The first that come with Celestia and the other whiich was created by Rassilon.Maybe its appearance can be none of these.But I would like to know if someone has a hunch about brown dwarf real physycal appearance(infrared observations,for example).Or is it all speculative?

Argh, &@#$ing stupid editor lost my original message, grrr!

It is mostly speculative, but we can make educated guesses. The best place to get an idea of what BDs might look like is at:

http://spider.ipac.caltech.edu/staff/da ... rison.html

The appearance varies - young BDs are hot enough to glow in the red end of the spectrum and actually may be hard to distinguish from M7-M9 V stars. But once the deuterium fusion in their cores shuts down, they cool off and contract slightly. First they'll form silicon and iron clouds in their atmospheres, then as they get really cool they'll start to condence water and methane.

I put my own artist's impression of a BD on the top of mymy Traveller webpage.

http://spider.ipac.caltech.edu/staff/da ... rison.html

I liked this link,but to have 2 textures of browndwafs,we should have bigger substars in the extrasolar.ssc.There is only half a dozen and only one is slightly bigger,with 17 Jupiter masses.But according to this diagram,it should have to be at least a 65 Jupiter mass to have a hotter browndwarf,and in this case,the Rassilon should be very apropriate.I would like to know if the astronomers already discovered brown dwarfs with at least 30 or even 65 Jupiter mass orbiting another star.In this case,should be included in the next extrasolar.What do you think?Or maybe the bigger browndwarfs are in the stars catalogue...

As I see it in the illustration there is no significant difference between the brown dwarf night and day side if the object is illuminated by a sun. Is this the case or does no-one really know yet?

Chaos Syndrome NotLogged wrote:As I see it in the illustration there is no significant difference between the brown dwarf night and day side if the object is illuminated by a sun. Is this the case or does no-one really know yet?

I presume that for the dimmer ones there should be a difference between day and night side (like the illustration on my webpage). Not sure about the brighter BDs though, since they're basically like stars themselves.

Yes, brown dwarfs will ultimately move to violet as they get cooler. I think the coldest brown dwarfs actually emit most of their light in ultraviolet.

What??

Ultraviolet implies higher energy...
how can that be?

Eburacum wrote:What??

Ultraviolet implies higher energy...
how can that be?

They won't. They'll emit most of their energy in the infrared. I think that they look more magenta as they cool because of the light they're absorbing, coupled with the fact that they're emitting low wavelength red light too.

Ah, thanks for that explanation

I had heard about the magenta/violet since earlier (not just here), and it fooled me to believe light was moving into these wavelengths.