A question about star's luminosity, temperature and mass.

[twofish-quant]

Also there are two H-R diagrams. Theorists work with bolometric luminosity versus effective temperature. You run the computer model, that gives you energy output and a radius were pressure goes to zero, you then calculate an effective temperature.

Observers work with color versus absolute magnitude. You measure the brightness of the star with two colored filters and plot on one axis, you take the visual magnitude correct for distance, plot on the other axis.

These two scales are roughly the same, but if you want to do precision work, then you have to apply all sorts of correction terms. In the observers diagram you are measuring color temperature whereas in the theorists diagram, you are measuring effective temperature. People go spend a ton of effort getting all this right, see..

http://iopscience.iop.org/1538-3881/120/2/1072/990160.text.html

The pattern in which everything becomes more complicated when you look at it closely is common thing in astronomy. For example if I ask you want time is it, do you mean TCG, TCG, UT, or TAI?

 

[JeffKoch]

Rishavutkarsh, I am sorry, but none of that is true. The luminosity of a star is determined by its radius and temperature.

Luminosity in what energy band? A star isn't a blackbody of course, it has a distribution of temperatures and opacities at different depths and so does not have a single defined "temperature" and "surface".

 

[~jet]

There is no good way to calculate the size of a stars photosphere based on luminosity that I know of - too many variables.

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 influencing the visible output/temperature of a star, and that seems fair... but to what level? a percent? Are there terms I can research that would lead to understanding or measuring likely metallicity based on initial environment? or to what effect and degree their presence incurs?

 

[robertrej]

I have been finding formula's for just about everything about stars and
was wondering if core and surface temperature has a formula as well?

Its 2,771,043 for the Sun as an example.( core / surface)kelvin.


Thanks
Bob