Wednesday, October 07, 2009

Using a mass of 5.03, the "dryworld" model is suggested to have a radius of 1.5 Earth’s, or 5938.5 miles. This works out to an average density of 1.49037037 and a gravity of 2.23555555 Earth. its escape velocity would be 1.831210892. (The corresponding numbers for the "waterworld" model (which i might as well call Perelandra) are 1.02381437, 1.740484429, and 1.720123115.)

Apparent size of the primary is 4.4 to 6.1 times the Sun as seen from Earth. (A hotter stellar temperature might reduce this somewhat.)

Blackbody at periastron is 380.3556349 & at apastron 323.6685502. Some estimates (based on an Earthlike atmosphere of mild greenhouse gases): [Dryworld model= "Metaluna"]

Albedo | Greenh. | Av °C | Peri | Apastr.

0.2-------21---------77 ----108----54
0.25------29---------80-----110----57
0.3-------38---------84-----113----61
0.35------47---------87-----115----65
0.4-------57---------91-----119----69
0.45------68---------95-----123----74
0.5-------79---------99-----126----78
0.55------90---------102----129----82

(The conditions around 0.35 & 47 seem more likely.)

With the antisolar point at √2 times the average, we get a temperature near 257 °C in all cases; in order for water to remain liquid, the atmospheric pressure would have to be at least 59 times Earth’s.

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