![SUN](/uploads/5/1/4/3/51436329/1106554.jpg?454)
SUN
Mean distance
from Earth
1.496×108 km
8 min 19 s at light speed
Visual brightness (V)
−26.74[1]
Absolute magnitude
4.83[1]
Spectral classification
G2V
Metallicity
Z = 0.0122[2]
Angular size
31.6–32.7′[3]
Adjectives
Solar
Orbital characteristics
Mean distance
from Milky Waycore
≈ 2.7×1017 km
27200 light-years
Galactic period
(2.25–2.50)×108 a
Velocity
≈ 220 km/s (orbit around the center of the Milky Way)
≈ 20 km/s (relative to average velocity of other stars in stellar neighborhood)
≈ 370 km/s[4] (relative to the cosmic microwave background)
Physical characteristics
Equatorialradius
696342±65 km[5]
109 × Earth[6]
Equatorialcircumference
4.379×106 km[6]
109 × Earth[6]
Flattening
9×10−6
Surface area
6.09×1012 km2[6]
12000 × Earth[6]
Volume
1.41×1018 km3[6]
1300000 × Earth
Mass
(1.98855±0.00025)×1030 kg[1]
333000 × Earth[1]
Averagedensity
1.408 g/cm3[1][6][7]
0.255 × Earth[1][6]
Centerdensity(modeled)
162.2 g/cm3[1]
12.4 × Earth
Equatorialsurface gravity
274.0 m/s2[1]
27.94 g
27542.29 cgs
28 × Earth[6]
Escape velocity
(from the surface)
617.7 km/s[6]
55 × Earth[6]
Temperature
Center (modeled): 1.57×107 K[1]
Photosphere (effective): 5778 K[1]
Corona: ≈ 5×106 K
Luminosity(Lsol)
3.846×1026 W[1]
≈ 3.75×1028 lm
≈ 98 lm/W efficacy
Meanradiance (Isol)
2.009×107 W·m−2·sr−1
Age
≈4.6 billion years[8][9]
Rotation characteristics
Obliquity
7.25°[1]
(to the ecliptic)
67.23°
(to the galactic plane)
Right ascension
of North pole[10]
286.13°
19 h 4 min 30 s
Declination
of North pole
+63.87°
63° 52' North
Siderealrotation period
(at equator)
25.05 days[1]
(at 16° latitude)
25.38 days[1]
25 d 9 h 7 min 12 s[10]
(at poles)
34.4 days[1]
Rotation velocity
(at equator)
7.189×103 km/h[6]
Photospheric composition (by mass)
Hydrogen
73.46%[11]
Helium
24.85%
Oxygen
0.77%
Carbon
0.29%
Iron
0.16%
Neon
0.12%
Nitrogen
0.09%
Silicon
0.07%
Magnesium
0.05%
Sulfur
0.04%
The Sun[a] is the star at the center of the Solar System and is by far the most important source of energy for life on Earth. It is a nearly perfect spherical ball of hot plasma,[12][13] with internal convective motion that generates a magnetic field via a dynamo process.[14] Its diameter is about 109 times that of Earth, and it has a mass about 330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System.[15] Chemically, about three quarters of the Sun's mass consists of hydrogen, whereas the rest is mostly helium, and much smaller quantities of heavier elements, including oxygen, carbon, neon and iron.[16]
The Sun is a G-type main-sequence star (G2V) based on spectral class and it is informally designated as a yellow dwarf. It formed approximately 4.567 billion[b][17] years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into an orbiting disk that became the Solar System. The central mass became increasingly hot and dense, eventually initiating thermonuclear fusion in its core. It is thought that almost all stars form by this process. The Sun is roughly middle age and has not changed dramatically for four billion[b] years, and will remain fairly stable for four billion more. However, after hydrogen fusion in its core has stopped, the Sun will undergo severe changes and become a red giant. It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury, Venus, and possibly Earth.
The enormous effect of the Sun on the Earth has been recognized since prehistoric times, and the Sun has been regarded by some cultures as a deity. Earth's movement around the Sun is the basis of the solar calendar, which is the predominant calendar in use today.
The Sun is a G-type main-sequence star that comprises about 99.86% of the mass of the Solar System. Once regarded by astronomers as a small and relatively insignificant star, the Sun has an absolute magnitude of +4.83. This is now estimated to be brighter than about 85% of the stars in the Milky Way, most of which arered dwarfs.[25][26] The Sun is a Population I, or heavy-element-rich,[c] star.[27] The formation of the Sun may have been triggered by shockwaves from one or more nearby supernovae.[28] This is suggested by a high abundance of heavy elements in the Solar System, such as gold and uranium, relative to the abundances of these elements in so-called Population II, heavy-element-poor, stars. These elements could most plausibly have been produced by endothermic nuclear reactions during a supernova, or by transmutation through neutron absorption within a massive second-generation star.[27]
The Sun is by far the brightest object in the sky, with an apparent magnitude of −26.74.[29][30] This is about 13 billion times brighter than the next brightest star,Sirius, which has an apparent magnitude of −1.46. The mean distance of the Sun to Earth is approximately 1 astronomical unit (about 150,000,000 km; 93,000,000 mi), though the distance varies as Earth moves from perihelion in January to aphelion in July.[31] At this average distance, light travels from the Sun to Earth in about 8 minutes and 19 seconds. The energy of this sunlight supports almost all life[d] on Earth by photosynthesis,[32] and drives Earth's climate and weather.
The Sun's radius can be measured from its center to the edge of the photosphere, the apparent visible surface of the Sun.[33] The Sun is a near-perfect sphere with an oblateness estimated at about 9 millionths,[34] which means that its polar diameter differs from its equatorial diameter by only 10 kilometres (6.2 mi).[35] The tidal effect of the planets is weak and does not significantly affect the shape of the Sun.[36] The Sun rotates faster at its equator than at its poles. This differential rotation is caused by convective motion due to heat transport and the Coriolis force due to the Sun's rotation. In a frame of reference defined by the stars, the rotational period is approximately 25.6 days at the equator and 33.5 days at the poles. Viewed from Earth as it orbits the Sun, the apparent rotational period of the Sun at its equator is about 28 days.[37]
Mean distance
from Earth
1.496×108 km
8 min 19 s at light speed
Visual brightness (V)
−26.74[1]
Absolute magnitude
4.83[1]
Spectral classification
G2V
Metallicity
Z = 0.0122[2]
Angular size
31.6–32.7′[3]
Adjectives
Solar
Orbital characteristics
Mean distance
from Milky Waycore
≈ 2.7×1017 km
27200 light-years
Galactic period
(2.25–2.50)×108 a
Velocity
≈ 220 km/s (orbit around the center of the Milky Way)
≈ 20 km/s (relative to average velocity of other stars in stellar neighborhood)
≈ 370 km/s[4] (relative to the cosmic microwave background)
Physical characteristics
Equatorialradius
696342±65 km[5]
109 × Earth[6]
Equatorialcircumference
4.379×106 km[6]
109 × Earth[6]
Flattening
9×10−6
Surface area
6.09×1012 km2[6]
12000 × Earth[6]
Volume
1.41×1018 km3[6]
1300000 × Earth
Mass
(1.98855±0.00025)×1030 kg[1]
333000 × Earth[1]
Averagedensity
1.408 g/cm3[1][6][7]
0.255 × Earth[1][6]
Centerdensity(modeled)
162.2 g/cm3[1]
12.4 × Earth
Equatorialsurface gravity
274.0 m/s2[1]
27.94 g
27542.29 cgs
28 × Earth[6]
Escape velocity
(from the surface)
617.7 km/s[6]
55 × Earth[6]
Temperature
Center (modeled): 1.57×107 K[1]
Photosphere (effective): 5778 K[1]
Corona: ≈ 5×106 K
Luminosity(Lsol)
3.846×1026 W[1]
≈ 3.75×1028 lm
≈ 98 lm/W efficacy
Meanradiance (Isol)
2.009×107 W·m−2·sr−1
Age
≈4.6 billion years[8][9]
Rotation characteristics
Obliquity
7.25°[1]
(to the ecliptic)
67.23°
(to the galactic plane)
Right ascension
of North pole[10]
286.13°
19 h 4 min 30 s
Declination
of North pole
+63.87°
63° 52' North
Siderealrotation period
(at equator)
25.05 days[1]
(at 16° latitude)
25.38 days[1]
25 d 9 h 7 min 12 s[10]
(at poles)
34.4 days[1]
Rotation velocity
(at equator)
7.189×103 km/h[6]
Photospheric composition (by mass)
Hydrogen
73.46%[11]
Helium
24.85%
Oxygen
0.77%
Carbon
0.29%
Iron
0.16%
Neon
0.12%
Nitrogen
0.09%
Silicon
0.07%
Magnesium
0.05%
Sulfur
0.04%
The Sun[a] is the star at the center of the Solar System and is by far the most important source of energy for life on Earth. It is a nearly perfect spherical ball of hot plasma,[12][13] with internal convective motion that generates a magnetic field via a dynamo process.[14] Its diameter is about 109 times that of Earth, and it has a mass about 330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System.[15] Chemically, about three quarters of the Sun's mass consists of hydrogen, whereas the rest is mostly helium, and much smaller quantities of heavier elements, including oxygen, carbon, neon and iron.[16]
The Sun is a G-type main-sequence star (G2V) based on spectral class and it is informally designated as a yellow dwarf. It formed approximately 4.567 billion[b][17] years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into an orbiting disk that became the Solar System. The central mass became increasingly hot and dense, eventually initiating thermonuclear fusion in its core. It is thought that almost all stars form by this process. The Sun is roughly middle age and has not changed dramatically for four billion[b] years, and will remain fairly stable for four billion more. However, after hydrogen fusion in its core has stopped, the Sun will undergo severe changes and become a red giant. It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury, Venus, and possibly Earth.
The enormous effect of the Sun on the Earth has been recognized since prehistoric times, and the Sun has been regarded by some cultures as a deity. Earth's movement around the Sun is the basis of the solar calendar, which is the predominant calendar in use today.
The Sun is a G-type main-sequence star that comprises about 99.86% of the mass of the Solar System. Once regarded by astronomers as a small and relatively insignificant star, the Sun has an absolute magnitude of +4.83. This is now estimated to be brighter than about 85% of the stars in the Milky Way, most of which arered dwarfs.[25][26] The Sun is a Population I, or heavy-element-rich,[c] star.[27] The formation of the Sun may have been triggered by shockwaves from one or more nearby supernovae.[28] This is suggested by a high abundance of heavy elements in the Solar System, such as gold and uranium, relative to the abundances of these elements in so-called Population II, heavy-element-poor, stars. These elements could most plausibly have been produced by endothermic nuclear reactions during a supernova, or by transmutation through neutron absorption within a massive second-generation star.[27]
The Sun is by far the brightest object in the sky, with an apparent magnitude of −26.74.[29][30] This is about 13 billion times brighter than the next brightest star,Sirius, which has an apparent magnitude of −1.46. The mean distance of the Sun to Earth is approximately 1 astronomical unit (about 150,000,000 km; 93,000,000 mi), though the distance varies as Earth moves from perihelion in January to aphelion in July.[31] At this average distance, light travels from the Sun to Earth in about 8 minutes and 19 seconds. The energy of this sunlight supports almost all life[d] on Earth by photosynthesis,[32] and drives Earth's climate and weather.
The Sun's radius can be measured from its center to the edge of the photosphere, the apparent visible surface of the Sun.[33] The Sun is a near-perfect sphere with an oblateness estimated at about 9 millionths,[34] which means that its polar diameter differs from its equatorial diameter by only 10 kilometres (6.2 mi).[35] The tidal effect of the planets is weak and does not significantly affect the shape of the Sun.[36] The Sun rotates faster at its equator than at its poles. This differential rotation is caused by convective motion due to heat transport and the Coriolis force due to the Sun's rotation. In a frame of reference defined by the stars, the rotational period is approximately 25.6 days at the equator and 33.5 days at the poles. Viewed from Earth as it orbits the Sun, the apparent rotational period of the Sun at its equator is about 28 days.[37]