### flux

Posted:

**Wed Feb 08, 2017 3:10 pm**How many times greater is the flux from a star that is 16.5 times hotter than the sun?

https://www.sciencebuddies.org/science-fair-projects/ask-an-expert/viewtopic.php?f=35&t=17344

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Posted: **Wed Feb 08, 2017 3:10 pm**

How many times greater is the flux from a star that is 16.5 times hotter than the sun?

Posted: **Fri Feb 10, 2017 9:16 am**

Hi rockyrm2003,

Let's assume that by "16.5 times hotter than the sun" you mean a "16.5 times the effective temperature of the sun".

The luminosity, L, of a star (that is, the flux of energy emitted by the star) is:

L = 4*pi*(radius of star)^2*Stephan-Boltzmann constant*(effective temperature of star)^4

Taking the ratio of the luminosity of the star to the luminosity of the Sun,

L_star = L_sun*(radius of star/radius of Sun)^2*(effective temperature of star/effective temperature of sun)^4

From this, we see that in addition to knowing the effective temperature of the star, we also need to know the radius of the star in question. Stellar mass, radius, and luminosity are all related to each other. But, to have a definite answer to your question, we would also need to know the radius of the star in question.

Let's assume that by "16.5 times hotter than the sun" you mean a "16.5 times the effective temperature of the sun".

The luminosity, L, of a star (that is, the flux of energy emitted by the star) is:

L = 4*pi*(radius of star)^2*Stephan-Boltzmann constant*(effective temperature of star)^4

Taking the ratio of the luminosity of the star to the luminosity of the Sun,

L_star = L_sun*(radius of star/radius of Sun)^2*(effective temperature of star/effective temperature of sun)^4

From this, we see that in addition to knowing the effective temperature of the star, we also need to know the radius of the star in question. Stellar mass, radius, and luminosity are all related to each other. But, to have a definite answer to your question, we would also need to know the radius of the star in question.

Posted: **Wed Mar 22, 2017 1:42 am**

tdaly wrote:Hi rockyrm2003,

Let's assume that by "16.5 times hotter than the sun" you mean a "16.5 times the effective temperature of the sun".

The luminosity, L, of a star (that is, the flux of energy emitted by the star) is:

L = 4*pi*(radius of star)^2*Stephan-Boltzmann constant*(effective temperature of star)^4

Taking the ratio of the luminosity of the star to the luminosity of the Sun,

L_star = L_sun*(radius of star/radius of Sun)^2*(effective temperature of star/effective temperature of sun)^4

From this, we see that in addition to knowing the effective temperature of the star, we also need to know the radius of the star in question. Stellar mass, radius, and luminosity are all related to each other. But, to have a definite answer to your question, we would also need to know the radius of the star in question.

I am still confused......would you please share its diagrammatic presentation to make more easy to understand!

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