Re: [nbos] Stellar Radius - Mass - Luminosity Parameters.hal-at-buffnet.netFri Feb 22nd, 2008The information I had/have is based on main sequence stars rather than giants, so I don't know how useful this will be... >From ASTRONOMY: A SELF TEACHING GUIDE by Dinah L. Moche page 82: Luminocity of Sun is approximately equal to mass to the 3.5 power. Luminocity = 4 pi R^2 (5.67 EE -8) T^4 There are other books that you may find useful depending on whether you want to buy them or not... World-Building: A writer's guide to constructing star systems and life-supporting planets by Stephen L. Gillet. That book contains formulas out the whazoo including the apparent diameter of the star from any planet at any distance from that star. In addition, it has formulas for correcting for the bolometric luminocity as compared against the apparent luminocity. I found it to be a very nicely explained book. WORLD-BUILDING does differ from ASTRONOMY above in listing the mass luminocity relation as being Luminocity is approximately equal to mass ^ 3.8 (as opposed to 3.5). It solves for the other side of the equation by saying that Mass approximately equal to Luminocity^.2632 GURPS FIRST IN: while it is useful for role playing games, it does have one feature that might be of interest - stellar masses for type III and type I stars (Giants and Super Giants). You can use interpolation to determine star masses and radii for those stars that fall between spectal types (ie a G3 III won't be listed, but it will fall between G0 and G5 class stars. For what it is worth, you can now pick up TRAVELLER 2300 as PDF documents from FAR FUTURES. The ENTIRE collection of books printed for that game system was made into PDF's and if I recall correctly, runs about \$35 plus s&h. 2300 AD has the math formulas for determing the spherical volume and thus mass of any given star based on density and radius. Thus, if you know for example, that the expected density of a star is expected to be 1.01 and you know its radius - you can determine its mass by virtue of the volumn formula. I don't know how much help this is, and I apologize if it isn't what you're looking for. :( Good luck :) _______________________________________________ Nbossoftware mailing list