Evolution of the solar luminosity, radius and effective temperature compared to the present-day Sun. After Ribas (2010)[1]
One nominal solar luminosity is defined by the International Astronomical Union to be 3.828×1026W.[2] This does not include the solar neutrino luminosity, which would add 0.023 L☉,[3] or 8.8×1024 W, i.e. a total of 3.916×1026 W (the mean energy of the solar photons is 26 MeV and that of the solar neutrinos 0.59 MeV, i.e. 2.27%; the Sun emits 9.2×1037 photons and as many neutrinos each second, of which 6.5×1014 per m2 reach the Earth each second). The Sun is a weakly variable star, and its actual luminosity therefore fluctuates.[4] The major fluctuation is the eleven-year solar cycle (sunspot cycle) that causes a quasi-periodic variation of about ±0.1%. Other variations over the last 200–300 years are thought to be much smaller than this.[5]
Solar luminosity is related to solar irradiance (the solar constant). Solar irradiance is responsible for the orbital forcing that causes the Milankovitch cycles, which determine Earthly glacial cycles. The mean irradiance at the top of the Earth's atmosphere is sometimes known as the solar constant, I☉. Irradiance is defined as power per unit area, so the solar luminosity (total power emitted by the Sun) is the irradiance received at the Earth (solar constant) multiplied by the area of the sphere whose radius is the mean distance between the Earth and the Sun:
where A is the unit distance (the value of the astronomical unit in metres) and k is a constant (whose value is very close to one) that reflects the fact that the mean distance from the Earth to the Sun is not exactly one astronomical unit.
^Ribas, Ignasi (February 2010), "The Sun and stars as the primary energy input in planetary atmospheres" (PDF), Solar and Stellar Variability: Impact on Earth and Planets, Proceedings of the International Astronomical Union, IAU Symposium, vol. 264, pp. 3–18, arXiv:0911.4872, Bibcode:2010IAUS..264....3R, doi:10.1017/S1743921309992298, S2CID 119107400
^"Resolution B3 on recommended nominal conversion constants for selected solar and planetary properties" (PDF). International Astronomical Union. 2015. Retrieved 5 June 2018.
^Vieira, L. E. A.; Norton, A.; Dudok De Wit, T.; Kretzschmar, M.; Schmidt, G. A.; Cheung, M. C. M. (2012). "How the inclination of Earth's orbit affects incoming solar irradiance" (PDF). Geophysical Research Letters. 39 (16): L16104 (8 pp.). Bibcode:2012GeoRL..3916104V. doi:10.1029/2012GL052950. insu-01179873.
^Noerdlinger, Peter D. (2008). "Solar Mass Loss, the Astronomical Unit, and the Scale of the Solar System". Celestial Mechanics and Dynamical Astronomy. 801: 3807. arXiv:0801.3807. Bibcode:2008arXiv0801.3807N.
Further reading
Sackmann, I.-J.; Boothroyd, A. I. (2003), "Our Sun. V. A Bright Young Sun Consistent with Helioseismology and Warm Temperatures on Ancient Earth and Mars", Astrophys. J., 583 (2): 1024–39, arXiv:astro-ph/0210128, Bibcode:2003ApJ...583.1024S, doi:10.1086/345408, S2CID 118904050
Foukal, P.; Fröhlich, C.; Spruit, H.; Wigley, T. M. L. (2006), "Variations in solar luminosity and their effect on the Earth's climate", Nature, 443 (7108): 161–66, Bibcode:2006Natur.443..161F, doi:10.1038/nature05072, PMID 16971941, S2CID 205211006
Pelletier, Jon D. (1996), "Variations in Solar Luminosity from Timescales of Minutes to Months", Astrophys. J., 463 (1): L41–L45, arXiv:astro-ph/9510026, Bibcode:1996ApJ...463L..41P, doi:10.1086/310049, S2CID 7372755
Stoykova, D. A.; Shopov, Y. Y.; Ford, D.; Georgiev, L. N.; et al. (1999), "Powerful Millennial-Scale Solar Luminosity Cycles and Their Influence Over Past Climates and Geomagnetic Field", Proceedings of the AGU Chapman Conference: Mechanisms of Millennial Scale Global Climate Change
solar, luminosity, solar, luminosity, unit, radiant, flux, power, emitted, form, photons, conventionally, used, astronomers, measure, luminosity, stars, galaxies, other, celestial, objects, terms, output, evolution, solar, luminosity, radius, effective, temper. The solar luminosity L is a unit of radiant flux power emitted in the form of photons conventionally used by astronomers to measure the luminosity of stars galaxies and other celestial objects in terms of the output of the Sun Evolution of the solar luminosity radius and effective temperature compared to the present day Sun After Ribas 2010 1 One nominal solar luminosity is defined by the International Astronomical Union to be 3 828 1026 W 2 This does not include the solar neutrino luminosity which would add 0 023 L 3 or 8 8 1024 W i e a total of 3 916 1026 W the mean energy of the solar photons is 26 MeV and that of the solar neutrinos 0 59 MeV i e 2 27 the Sun emits 9 2 1037 photons and as many neutrinos each second of which 6 5 1014 per m2 reach the Earth each second The Sun is a weakly variable star and its actual luminosity therefore fluctuates 4 The major fluctuation is the eleven year solar cycle sunspot cycle that causes a quasi periodic variation of about 0 1 Other variations over the last 200 300 years are thought to be much smaller than this 5 Contents 1 Determination 2 See also 3 References 4 Further reading 5 External linksDetermination EditSolar luminosity is related to solar irradiance the solar constant Solar irradiance is responsible for the orbital forcing that causes the Milankovitch cycles which determine Earthly glacial cycles The mean irradiance at the top of the Earth s atmosphere is sometimes known as the solar constant I Irradiance is defined as power per unit area so the solar luminosity total power emitted by the Sun is the irradiance received at the Earth solar constant multiplied by the area of the sphere whose radius is the mean distance between the Earth and the Sun L 4 p k I A 2 displaystyle L odot 4 pi kI odot A 2 where A is the unit distance the value of the astronomical unit in metres and k is a constant whose value is very close to one that reflects the fact that the mean distance from the Earth to the Sun is not exactly one astronomical unit See also EditSun Solar mass Solar radius Nuclear fusion Active region Triple alpha processReferences Edit Ribas Ignasi February 2010 The Sun and stars as the primary energy input in planetary atmospheres PDF Solar and Stellar Variability Impact on Earth and Planets Proceedings of the International Astronomical Union IAU Symposium vol 264 pp 3 18 arXiv 0911 4872 Bibcode 2010IAUS 264 3R doi 10 1017 S1743921309992298 S2CID 119107400 Resolution B3 on recommended nominal conversion constants for selected solar and planetary properties PDF International Astronomical Union 2015 Retrieved 5 June 2018 Bahcall John N 1989 Neutrino Astrophysics Cambridge University Press p 79 ISBN 978 0 521 37975 5 Vieira L E A Norton A Dudok De Wit T Kretzschmar M Schmidt G A Cheung M C M 2012 How the inclination of Earth s orbit affects incoming solar irradiance PDF Geophysical Research Letters 39 16 L16104 8 pp Bibcode 2012GeoRL 3916104V doi 10 1029 2012GL052950 insu 01179873 Noerdlinger Peter D 2008 Solar Mass Loss the Astronomical Unit and the Scale of the Solar System Celestial Mechanics and Dynamical Astronomy 801 3807 arXiv 0801 3807 Bibcode 2008arXiv0801 3807N Further reading EditSackmann I J Boothroyd A I 2003 Our Sun V A Bright Young Sun Consistent with Helioseismology and Warm Temperatures on Ancient Earth and Mars Astrophys J 583 2 1024 39 arXiv astro ph 0210128 Bibcode 2003ApJ 583 1024S doi 10 1086 345408 S2CID 118904050 Foukal P Frohlich C Spruit H Wigley T M L 2006 Variations in solar luminosity and their effect on the Earth s climate Nature 443 7108 161 66 Bibcode 2006Natur 443 161F doi 10 1038 nature05072 PMID 16971941 S2CID 205211006 Pelletier Jon D 1996 Variations in Solar Luminosity from Timescales of Minutes to Months Astrophys J 463 1 L41 L45 arXiv astro ph 9510026 Bibcode 1996ApJ 463L 41P doi 10 1086 310049 S2CID 7372755 Stoykova D A Shopov Y Y Ford D Georgiev L N et al 1999 Powerful Millennial Scale Solar Luminosity Cycles and Their Influence Over Past Climates and Geomagnetic Field Proceedings of the AGU Chapman Conference Mechanisms of Millennial Scale Global Climate ChangeExternal links EditLISIRD LASP Interactive Solar Irradiance Datacenter Stellar Luminosity Calculator Solar Luminosity Variation of Solar LuminosityPortals Physics Astronomy Stars Outer space Solar System Science Retrieved from https en wikipedia org w index php title Solar luminosity amp oldid 1130376674, wikipedia, wiki, book, books, library,
