by Ann » Mon Aug 22, 2011 12:43 pm
nstahl wrote:A question about energy balance occurs to me. A key word here is "reflected". So the planet is absorbing immense amounts of energy; it must be re-radiating it at different wavelengths, and one of the links I've seen refers to it being like glowing embers. Does anyone here know what kind of information we've been able to get from the spectrum of that re-radiated energy?
Considering the kind of star that this planet orbits, a G0V type of star, slightly but not a lot hotter than the Sun, the planet might be warmed to brown dwarf-like temperatures.
http://en.wikipedia.org/wiki/Brown_dwarf writes:
Some brown dwarfs emit X-rays; and all "warm" dwarfs continue to glow tellingly in the red and infrared spectra until they cool to planetlike temperatures (under 1000 K).
So the planet won't emit much visual light unless it is hotter than 1000K.
http://en.wikipedia.org/wiki/Brown_dwarf also writes:
Because of the absorption of sodium and potassium in the green part of the spectrum of T dwarfs, the actual appearance of T dwarfs to human visual perception is estimated to be not brown, but the color of
magenta coal tar dye.
Magenta coal tar dye, eh? Sounds like today's APOD planet to me. Maybe the planet looks
like this.
A lot of elements and molecules have spectral signatures in the infrared part of the spectrum, so it should definitely be possible to find out the composition of the atmosphere of the planet, if its infrared signature can be separated from the signature of the star.
Ann
[quote="nstahl"]A question about energy balance occurs to me. A key word here is "reflected". So the planet is absorbing immense amounts of energy; it must be re-radiating it at different wavelengths, and one of the links I've seen refers to it being like glowing embers. Does anyone here know what kind of information we've been able to get from the spectrum of that re-radiated energy?[/quote]
Considering the kind of star that this planet orbits, a G0V type of star, slightly but not a lot hotter than the Sun, the planet might be warmed to brown dwarf-like temperatures.
[quote]http://en.wikipedia.org/wiki/Brown_dwarf writes:
Some brown dwarfs emit X-rays; and all "warm" dwarfs continue to glow tellingly in the red and infrared spectra until they cool to planetlike temperatures (under 1000 K).[/quote]
So the planet won't emit much visual light unless it is hotter than 1000K.
[quote]http://en.wikipedia.org/wiki/Brown_dwarf also writes:
Because of the absorption of sodium and potassium in the green part of the spectrum of T dwarfs, the actual appearance of T dwarfs to human visual perception is estimated to be not brown, but the color of [b][color=#FF00FF]magenta[/color] [size=115][color=#000000]coal tar[/color][/size] [/b]dye.[/quote]
Magenta coal tar dye, eh? Sounds like today's APOD planet to me. Maybe the planet looks [url=http://en.wikipedia.org/wiki/File:T-dwarf-nasa-hurt.png]like this[/url].
A lot of elements and molecules have spectral signatures in the infrared part of the spectrum, so it should definitely be possible to find out the composition of the atmosphere of the planet, if its infrared signature can be separated from the signature of the star.
Ann