Re: Habitability of Gliese 876c & d

brdavis@xxxxxxxx wrote:

   Sorry I let this question lay so long. The original idea is correct:
certain atmospheres have better IR emitters than others, and so act as
"thermostats" to lower the exosphere temperature. For Mars, the
exosphere temperature would "normally" be at about 2,000 K, but CO
serves as a great radiator, and Viking measured an exobase temperature
os just 210 K at 175 km.


Neat, and thanks.

I wonder how effective CO would be as a radiator at lower temperature.
Specificially, I wonder how effective it would be at keeping
the exosphere cool on a small body in the outer solar system.
What I want is a smallish body (larger than Pluto, but smaller
than Mars) in the Kuiper Belt that could retain 3He in its
atmosphere.  CO has a vapor pressure of 1 millitorr at 38 K;
that might be enough to be interesting.

	Paul
.