Fact Sheet: The Sun (Comparison with Earth)
Bulk parameters
Sun | Earth | Ratio (Sun/Earth) | |
Mass (1024 kg) | 1,988,500. | 5.9726 | 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. | 5514. | 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 |
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 Pressure at bottom of photosphere (optical depth = 1): 125 mb Effective temperature: 5778 K Temperature at top of photosphere: 4400 K Temperature at bottom of photosphere: 6600 K Temperature at top of chromosphere: ~30,000 K Photosphere thickness: ~500 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
Note: Fact Sheet is taken from NASA website: http://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html
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