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Formulas
http://forum.celestialmatters.org/viewtopic.php?f=2&t=809
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Author:  AstroCurious [ Sat, 06-02-16, 14:35 GMT ]
Post subject:  Formulas

Hey Everyone I was wondering which formula would you use to calculate the mass of helium that is created in the Sun's core over its lifetime?

Author:  t00fri [ Sat, 06-02-16, 15:34 GMT ]
Post subject:  Re: Formulas

AstroCurious wrote:
Hey Everyone I was wondering which formula would you use to calculate the mass of helium that is created in the Sun's core over its lifetime?


I would first calculate the number of Helium nuclei produced each second in the Sun's core. That you get easily by dividing the sun's total energy output [J/sec] by the energy for one fusion reaction [J/reaction]. The result has dimension [#reactions/sec] = [#He nuclei/sec] Aha! Then multiply by the mass of one Helium nucleus. Finally, multiply with the lifetime of the Sun in seconds...which should give the total mass of the created He during the sun's lifetime...

Welcome at CelestialMatters,
Fridger

Author:  AstroCurious [ Sun, 07-02-16, 5:37 GMT ]
Post subject:  Re: Formulas

t00fri wrote:
AstroCurious wrote:
Hey Everyone I was wondering which formula would you use to calculate the mass of helium that is created in the Sun's core over its lifetime?


I would first calculate the number of Helium nuclei produced each second in the Sun's core. That you get easily by dividing the sun's total energy output [J/sec] by the energy for one fusion reaction [J/reaction]. The result has dimension [#reactions/sec] = [#He nuclei/sec] Aha! Then multiply by the mass of one Helium nucleus. Finally, multiply with the lifetime of the Sun in seconds...which should give the total mass of the created He during the sun's lifetime...

Welcome at CelestialMatters,
Fridger


Thank you very much t00fri both for the formula and the welcome!

I apologize if this is a stupid question and slightly unrelated to this topic, but it is one about the relationship between luminosity and apparent brightness. Since its an astronomy dedicated forum say there is a star that is 25 times more luminous than the Sun, if it were located at a distance of 1 AU from Earth same as the Sun would its apparent brightness be 25x that of the Sun's? However since the relationship between distance and apparent brightness is inverse, if this same theoretical star was located at a distance of 5 AU would it have the same apparent brightness as the Sun, since the square root of 25 is 5 ? Since distance squared equals apparent brightness. I am just wondering if I have this concept right or?

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