The Nacreous Oughts

01 October 2018


(theseastorm via)

Writers who use an extensive vocabulary (Ryling, A Theroux, Pynchon) are like microtonal composers; they just need more notes.

Rumi & "The Guests."

The Vulcan discovery paper finds an 8.47 earth-mass planet in a 42.378 day orbit around the star HD 26965 (omicron-2 Eridani A, HIP 19849, "Keid," HR 1325 & Gliese 166A), which is a triple with a white dwarf-red dwarf pair at 82" (some 418 AU), making one revolution in some 8000 years. The age of the system is given as 6.9 billion years--though the white dwarf may only be 122 million years old & must have been some kind of red giant before that (& then a "planetary nebula"--thought to be toxic for any nearby planetary life). Hipparchos gives the parallax as 0".1985657 & the visual magnitude of the K0 V primary as 4.43. It is metal-poor (Fe/H -0.42).

Some more general reflections...

Using a Bolometric Correction of -0.21 & a stellar temperature (given) of 5072 K, I get a visual luminosity of 0.373414809 & a bolometric luminosity of 0.453097366. (The radius works out to be 0.880224122--given as 0.87--so perhaps the BC should be a tad less.) With a stellar mass of 0.78 & a revolution period of 0.116022619, I find the semimajor axis of the planet to be 0.218974383. This gives a blackbody temperature of 490.3502805 (compare Venus at 328 & Mercury at 449): this is not by any means a habitable world! (Too bad nobody figured this in the dozens of news reports about "Spock's home planet"...)

If the planetary mass is 8.47 (given), its radius should be around 1.76; then I derive a density of 1.55, gravity of 2.73, & escape velocity of 2.19 times the Earth's (safely under the 3.19 that would hold molecular hydrogen at this temperature, thus producing a gas giant instead of a rocky world at start). The real question is how much of its original atmosphere will be left after its violent history with the evolution of 40 Eridani B (now 0.573 times the mass of the sun, but formerly at least an F-type star with some twice this). If I just plug in a low albedo like Mars's (0.15), I get a greybody temperature of 198 C. Greenhouse effect would presumably increase this. At surface temperatures such as this (I am ignoring for the moment the problem of a trapped--rotation climate), the atmospheric pressure must be at least 16 atmospheres for water not to boil. Would there still be this much left in the end? Could even a highly advanced civilization survive 10,000 years of living underground?


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