User:Zimriel

From Mass Effect Wiki

I have not yet finished this game as of now. However I have got close to the endgame, and read "Revelation". I am currently awaiting "Bring Down The Sky" for PC before I finish the game proper.

I started my wikia career here by working on planetary mass for planets with both radius and g. User DRY has since auto-generated all this, and has also included Keplerian ratios for planets with both distance and orbital-period (i.e., year length). Keplerian ratios are just the stellar mass, which in main-sequence stars gives the luminosity and radius as well. I understand we have got Pax, Macedon, Hercules, Cacus, Acheron, Century, Farinata and (in descriptions rather than statistics) Gorgon and Phoenix sorted out this way. Fortuna the red dwarf is another possibility; its mass can't be much different from 0.4. Ming offered a less precise determination - somewhere around 60 - but still, good enough I believe.

Caspian, Grissom, and Herschel were each described as a "hot blue star" so consistently that we can give each a stellar class. But this class (O) could be any mass over 20 sols. Not useful for Keplerian purposes. Vamshi has major problems in that it is a binary system - one a white subgiant and the other a red giant.

Currently I am thinking up ways to derive the luminosity of suns from airless, dark (albedo=0) worlds with a known temperature and orbital-period. I had tried this for the Sparta-Tremanre system but I'd got Kepler's ratio inversed in those days (d'oh!).

I'm testing this out by calculating albedo in airless worlds: 1- [(distance² * (273.15+temp)⁴) / (278.3⁴ * luminosity)]. (http://www.shatters.net/forum/viewtopic.php?f=7&t=3154)

The Cacus system is my laboratory. So, for Chohe, 1- (3.7 ^2 * (273.15+11)^4)/(278.3^4 * 6) = -1.48

[edit] So, what have we found?

The developers seem to have used orbital period as a proxy for distance from the sun, and to have rule-of-thumbed a set of planetary temperatures per system. When they added orbital distance, they tried and generally succeeded in maintaining Kepler's famous ratio across planets, and in relating this to the class of the star (M red dwarf, O/B blue giant, etc). So my initial thought that "Kepler is orbiting in his grave" turns out to be overwrought.

Where they fell down was in calculating those planetary temperatures. Almost all of these temperatures are too high, even assuming zero albedo. Atmosphere doesn't help when it doesn't exist or has no greenhouse properties; in fact I suspect some of these atmospheres (sulphur dioxide in particular) are smogs which shade the planet even more. I excused Chohe and the other Cacus planets as an effect of youth, but I was reluctant to make excuses for other systems. Kepler rests in relative peace; it's the irate husks of Stefan and Boltzmann whom the developers will have to keep at bay.

There's also a small problem with close to half of ME's "gas giants" - namely, they're not gas giants. The developers did keep their radii under 80000 km, saving them from hydrogen collapse and stellar fusion. Unfortunately they also copy-pasted "typical hydrogen-helium gas giant" too often. Gas giants don't exist below 60000 km at Saturn's temperature; any less than that, and the hydrogen hasn't enough mass to stick around. Of course the proverbial "hot Jupiter" hasn't a ghost of a chance at this radius. Anything at 25000 km or less, in particular, is in Uranus / Neptune territory. Also, if the planet is in an OB class system then its radius is inflated by extreme youth. I've mentioned this in their Trivia sections.