Sun

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This airticle is aboot the starn. For ither uisses, see Sun (disambiguation).
The Sun Sun symbol.svg
Sun white.jpg
Sun wi sunspats an limm daurkenin as seen in veesible licht wi solar filter.
Observation data
Mean distance
frae Yird
1 au1.496×108 km
8 min 19 s at licht speed
Visual brightness (V) −26.74[1]
Absolute magnitude 4.83[1]
Spectral classification G2V[2]
Metallicity Z = 0.0122[3]
Angular size 31.6–32.7 meenits o arc[4]
Adjectives Solar
Orbital chairactereestics
Mean distance
from Milky Way core
≈ 2.7×1017 km
27,200 light-years
Galactic period (2.25–2.50)×108 yr
Velocity ≈ 220 km/s (orbit aroond the centre o the Milky Way)
≈ 20 km/s (relative tae average velocity o ither starns in stellar neeghbourheid)
≈ 370 km/s[5] (relative tae the cosmic microwave backgrund)
Pheesical chairactereestics
Equatorial radius 695,700 km,[6]
696,392 km[7]
109 × Yird[8]
Equatorial circumference 4.379×106 km[8]
109 × Yird[8]
Flattenin 9×10−6
Surface aurie 6.09×1012 km2[8]
12,000 × Yird[8]
Vollum 1.41×1018 km3[8]
1,300,000 × Yird
Mass (1.98855±0.00025)×1030 kg[1]
333,000 × Yird[1]
Average density 1.408 g/cm3[1][8][9]
0.255 × Yird[1][8]
Center density (modeled) 162.2 g/cm3[1]
12.4 × Yird
Equatorial surface gravity 274.0 m/s2[1]
27.94 g
27,542.29 cgs
28 × Yird[8]
Moment o inertia factor 0.070[1] (estimate)
Escape velocity
(from the surface)
617.7 km/s[8]
55 × Yird[8]
Temperatur Center (modeled): 1.57×107 K[1]
Photosphere (effective): 5,772 K[1]
Corona: ≈ 5×106 K
Luminosity (Lsol) 3.828×1026 W[1]
≈ 3.75×1028 lm
≈ 98 lm/W efficacy
Mean radiance (Isol) 2.009×107 W·m−2·sr−1
Age ≈ 4.6 billion years[10][11]
Rotation chairactereestics
Obliquity 7.25°[1]
(to the ecliptic)
67.23°
(tae the galactic plane)
Right ascension
of North pole[12]
286.13°
19 h 4 min 30 s
Declination
o North pole
+63.87°
63° 52' North
Sidereal rotation period
(at equator)
25.05 d[1]
(at 16° latitude) 25.38 d[1]
25 d 9 h 7 min 12 s[12]
(at powls) 34.4 d[1]
Rotation velocity
(at equator)
7.189×103 km/h[8]
Photospheric composeetion (bi mass)
Hydrogen 73.46%[13]
Helium 24.85%
Oxygen 0.77%
Caurbon 0.29%
Airn 0.16%
Neon 0.12%
Nitrogen 0.09%
Silicon 0.07%
Magnesium 0.05%
Sulfur 0.04%

The Sun is the starn at the centre o the Solar Seestem. It is a nearly perfect sphere o het plasma,[14][15] wi internal convective motion that generates a magnetic field via a dynamo process.[16] It is bi faur the maist important soorce o energy for life on Yird. Its diameter is aboot 1.39 million kilometres, i.e. 109 times that o Yird, an its mass is aboot 330,000 times that o Yird, accoontin for aboot 99.86% o the tot mass o the Solar Seestem.[17] Aboot three quarters o the Sun's mass conseests o hydrogen (~73%); the rest is maistly helium (~25%), wi muckle smawer quantities o hivier elements, includin oxygen, caurbon, neon, an airn.[18]

The Sun is a G-teep main-sequence starn (G2V) based on its spectral cless. As sic, it is informally an nae completely accurately referred tae as a yellae dwarf (its licht is closer tae white nor yellae). It formed approximately 4.6 billion[lower-alpha 1][10][19] years ago frae the gravitational collapse o maiter within a region o a lairge molecular clood. Maist o this maiter gaithered in the centre, whauras the rest flattened intae an orbitin disk that becam the Solar Seestem. The central mass becam sae het an dense that it eventually ineetiatit nuclear fusion in its core. It is thocht that awmaist aw starms form bi this process.

The Sun is aboot middle-aged; it haes nae chynged dramatically for mir than fower billion[lower-alpha 1] years, an will remeen fairly stable for mair nor anither five billion years. It currently fuzes aboot 544 million tonnes o hydrogen intae helium ivery seicont, converting 3.6 million tonnes o maiter into energy ivery seicont as a result. This energy, that can take atween 10,000 an 170,000 years tae escape frae its core, is the soorce o the Sun's licht an heat. In aboot 5 billion years, whan hydrogen fusion in its core haes dimeenished tae the point at which the Sun is na langer in hydrostatic equilibrium, the core o the Sun will experience a merkit increase in density an temperatur while its ooter layers expand tae eventually acome a red giant. It is calculatit that the Sun will acome sufficiently lairge tae engulf the current orbits o Mercury an Venus, an render Yird uninhabitable. Efter this, it will shed its ooter layers an acome a dense teep o cuilin starn kent as a white dwarf, that na langer produces energy bi fusion, but still glowes an gies aff heat frae its previous fusion.

The enormous effect o the Sun on Yird haes been recognised syne prehistoric times, an the Sun haes been regairdit bi some culturs as a deity. The synodic rotation o Yird an its orbit aroond the Sun are the basis o solar calendars, ane o which is the predominant calendar in uise the day.

Notes[eedit | eedit soorce]

  1. 1.0 1.1 Aw nummers in this aorticle are short scale. Ane billion is 109, or 1,000,000,000.

References[eedit | eedit soorce]

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 Williams, D. R. (1 Julie 2013). "Sun Fact Sheet". NASA Goddard Space Flight Center. Retrieved 12 August 2013. 
  2. Zombeck, Martin V. (1990). Handbook of Space Astronomy and Astrophysics 2nd edition. Cambridge University Press. 
  3. Asplund, M.; Grevesse, N.; Sauval, A. J. (2006). "The new solar abundances – Part I: the observations". Communications in Asteroseismology. 147: 76–79. Bibcode:2006CoAst.147...76A. doi:10.1553/cia147s76. 
  4. "Eclipse 99: Frequently Asked Questions". NASA. Archived frae the oreeginal on 27 Mey 2010. Retrieved 24 October 2010. 
  5. Hinshaw, G.; et al. (2009). "Five-year Wilkinson Microwave Anisotropy Probe observations: data processing, sky maps, and basic results". The Astrophysical Journal Supplement Series. 180 (2): 225–245. arXiv:0803.0732Freely accessible. Bibcode:2009ApJS..180..225H. doi:10.1088/0067-0049/180/2/225. 
  6. Mamajek, E.E.; Prsa, A.; Torres, G.; et, al. (2015). "IAU 2015 Resolution B3 on Recommended Nominal Conversion Constants for Selected Solar and Planetary Properties". arXiv:1510.07674 [astro-ph.SR]. 
  7. Emilio, Marcelo; Kuhn, Jeff R.; Bush, Rock I.; Scholl, Isabelle F. (2012), "Measuring the Solar Radius from Space during the 2003 and 2006 Mercury Transits", The Astrophysical Journal, 750 (2): 135, arXiv:1203.4898Freely accessible, Bibcode:2012ApJ...750..135E, doi:10.1088/0004-637X/750/2/135 
  8. 8.00 8.01 8.02 8.03 8.04 8.05 8.06 8.07 8.08 8.09 8.10 8.11 "Solar System Exploration: Planets: Sun: Facts & Figures". NASA. Archived frae the oreeginal on 2 Januar 2008. 
  9. Ko, M. (1999). Elert, G., ed. "Density of the Sun". The Physics Factbook. 
  10. 10.0 10.1 Bonanno, A.; Schlattl, H.; Paternò, L. (2008). "The age of the Sun and the relativistic corrections in the EOS". Astronomy and Astrophysics. 390 (3): 1115–1118. arXiv:astro-ph/0204331Freely accessible. Bibcode:2002A&A...390.1115B. doi:10.1051/0004-6361:20020749. 
  11. Connelly, JN; Bizzarro, M; Krot, AN; Nordlund, Å; Wielandt, D; Ivanova, MA (2 November 2012). "The Absolute Chronology and Thermal Processing of Solids in the Solar Protoplanetary Disk". Science. 338 (6107): 651–655. Bibcode:2012Sci...338..651C. doi:10.1126/science.1226919. PMID 23118187. Retrieved 17 Mairch 2014. (registration needit)
  12. 12.0 12.1 Seidelmann, P. K.; et al. (2000). "Report Of The IAU/IAG Working Group On Cartographic Coordinates And Rotational Elements Of The Planets And Satellites: 2000". Retrieved 22 Mairch 2006. 
  13. "The Sun's Vital Statistics". Stanford Solar Center. Retrieved 29 Julie 2008.  Citing Eddy, J. (1979). A New Sun: The Solar Results From Skylab. NASA. p. 37. NASA SP-402. 
  14. "How Round is the Sun?". NASA. 2 October 2008. Retrieved 7 Mairch 2011. 
  15. "First Ever STEREO Images of the Entire Sun". NASA. 6 Februar 2011. Retrieved 7 Mairch 2011. 
  16. Charbonneau, P. (2014). "Solar Dynamo Theory". Annual Review of Astronomy and Astrophysics. 52: 251–290. Bibcode:2014ARA&A..52..251C. doi:10.1146/annurev-astro-081913-040012. 
  17. Woolfson, M. (2000). "The origin and evolution of the solar system". Astronomy & Geophysics. 41 (1): 12. Bibcode:2000A&G....41a..12W. doi:10.1046/j.1468-4004.2000.00012.x. 
  18. Basu, S.; Antia, H. M. (2008). "Helioseismology and Solar Abundances". Physics Reports. 457 (5–6): 217–283. arXiv:0711.4590Freely accessible. Bibcode:2008PhR...457..217B. doi:10.1016/j.physrep.2007.12.002. 
  19. Connelly, James N.; Bizzarro, Martin; Krot, Alexander N.; Nordlund, Åke; Wielandt, Daniel; Ivanova, Marina A. (2 November 2012). "The Absolute Chronology and Thermal Processing of Solids in the Solar Protoplanetary Disk". Science. 338 (6107): 651–655. Bibcode:2012Sci...338..651C. doi:10.1126/science.1226919. PMID 23118187.