Recent content by ~jet

What I am most interested in is having an acceptable approximation of luminosity, radius, surface temperature (and thus color) based on initial mass and approximate age. I'm not coming at the problem based on observed stars, but on initial mass. Someone else 'round here mentioned metallicity...

http://www.youtube.com/watch?v=S_d-gs0WoUw&feature=fvwrel" ... its not really any surprise that these are coming to light only in recent years. We're getting better at this

Hah! Much appreciated! I shall investigate.

One problem with GM is less the genetics and more those who are disseminating said genetics; to wit, Monsanto who has arranged for local legislations in India and Iraq to make it illegal to save seeds. In tandem with this and their genetically modified strains which they sell for much larger...

Solved it; I was unwittingly trying to combine erg/s with watts

Of course; I'm familiar with the concept of shells of fusing different elements... what I wasn't as certain about is what is there that prevents a little helium from being fused along the way prior to the formation of the first helium core? I have some difficulty perceiving the mechanisms by...

Sure; BG is more luminous but due to its bloated dimensions, that is spread out so much more dramatically than either the sun or proxima centauri... you average down (for lack of a better term) to a lower, redder, cooler temperature despite the greater output. I am curious... I've ready that...

Perhaps I'm also asking the wrong question; I may still be blending my units poorly. T = \sqrt[4]{\frac{L}{A\sigma}} and I try to read this in units: \frac{erg/s}{\frac{cm^{2} erg}{s cm^{2} K^{4}}} If that isn't butchered, it does have a pleasing cascade of cancellations that lead me to...

Kay, so still doing something wrong... I'm getting 32486K for a sunmass star when I use what wikipedia claims. Am I misconstruing your equation when I flip it to L = \left(\left( \frac{M}{M_{Sun}} \right)^{3.5}\right)L_{Sun}. Further, why do you say 3.5 and wikipedia claim 4?

Sure, but that's observing only the consequences of the mechanics going on rather than addressing them directly. If not for the energy inside producing resistance to a mass's overall gravity, you couldn't have a hydrostatic equilibrium determining said mass's radius at any given point in time.

In any event, I shall plug away it at again; converting my radius to cm, I was able to get closER (as (erg/s)/(cm2erg/scm2K4) canceled down a lot easier)... at my next opportunity, I see what happens when I try that as you show it instead.

pulled it from http://en.wikipedia.org/wiki/Mass–luminosity_relation ... I may be misusing the proportionality bit. Have we really not worked out how to model these based purely on mass yet? (i.e., independent of having to use the sun as a comparator.)

Aside from opacity, would steadily decreasing mass (through dissemination of solar wind, energy, CMEs, etc) also technically increase a star's mass as it ages during its main sequence? Less gravity = less inward pressure = new hydrostatic equilibrium upwards = wider radius = more surface area...

Yip yip, that's what I mean; good to hear. the code is simple python, accepting solar masses as an argument: star.mass = 1.98892e+30 (kg) star.luminosity = star.mass ** 3.5 (1.1095850642735086e+106) star.radius = (star.mass ** 0.8) * solar_radius (~695,500,000m) star.surface_area = (4...

Oh, I believe it; that's why I was surprised not to find a 'stellar' equation that could simply equate reasonably predictable stellar 'characteristics' based purely on initial mass and current age (the two details I will know at the outset of my programming.)