Sun

SUN

                                                     Sun          Earth      Ratio (Sun/Earth)
Mass (10²⁴ kg)                         1,989,100.      5.9736        333,000.
GM (x 10⁶ km³/s²)                      132,712.      0.3986        333,000.
Volume (10¹² km³)                   1,412,000.       1.083      1,304,000.
Volumetric mean radius (km)        696,000.        6371.            109.2
Mean density (kg/m³)                       1408.        5515.            0.255
Surface gravity (eq.) (m/s²)              274.0          9.78              28.0
Escape velocity (km/s)                     617.6        11.19              55.2
Ellipticity                                     0.00005      0.0034            0.015
Moment of inertia (I/MR²)               0.059      0.3308            0.178
Visual magnitude V(1,0)                  -26.74        -3.86                -
Absolute magnitude                          +4.83
Luminosity (10²⁴ J/s)                       384.6
Mass conversion rate (10⁶ kg/s)        4300.
Mean energy production (10^-3 J/kg) 0.1937
Surface emission (10⁶ J/m²s)            63.29
Spectral type                                   G2 V

Model values at center of Sun:
Central pressure:       2.477 x 10¹¹ bar
Central temperature: 1.571 x 10⁷ K
Central density:         1.622 x 10⁵ kg/m³

Rotational and Orbital parameters

                                          Sun        Earth      Ratio (Sun/Earth)
Sidereal rotation period (hrs)*         609.12       23.9345     25.449     
Obliquity to ecliptic (deg.)              7.25       23.45        0.309
Speed relative to nearby stars (km/s)     19.4

*This is the adopted period at 16 deg. latitude - the actual rotation rate varies with latitude L as:
( 14.37 - 2.33 sin² L - 1.56 sin⁴ L ) deg/day

North Pole of Rotation

Right Ascension:     286.13
Declination    :        63.87
Reference Date :     1.5 Jan 2000 (JD 2451545.0)

Sun Observational Parameters

Apparent diameter from Earth
        At 1 A.U.(seconds of arc)  1919.
        Maximum (seconds of arc)   1952.
        Minimum (seconds of arc)   1887.
Distance from Earth
        Mean (10⁶ km)              149.6
        Minimum (10⁶ km)           147.1
        Maximum (10⁶ km)           152.1

Solar Magnetic Field

Typical magnetic field strengths for various parts of the Sun

Polar Field: 1 - 2 Gauss
Sunspots: 3000 Gauss
Prominences: 10 - 100 Gauss
Chromospheric plages: 200 Gauss
Bright chromospheric network: 25 Gauss
Ephemeral (unipolar) active regions: 20 Gauss

Solar Atmosphere

Surface Gas Pressure (top of photosphere): 0.868 mb
Effective temperature: 5778 K
Temperature at bottom of photosphere: 6600 K
Temperature at top of photosphere: 4400 K
Temperature at top of chromosphere: ~30,000 K
Photosphere thickness: ~400 km
Chromosphere thickness: ~2500 km
Sun Spot Cycle: 11.4 yr.

Photosphere Composition:
Major elements: H - 90.965%, He - 8.889%
Minor elements (ppm): O - 774, C - 330, Ne - 112, N - 102
Fe - 43, Mg - 35, Si - 32, S - 15