Sun Fact Sheet

Sun/Earth Comparison

Bulk parameters



Sun

Earth Ratio

(Sun/Earth) Mass (1024 kg) 1,988,500. 5.9724 333,000. GM (x 106 km3/s2) 132,712. 0.39860 333,000. Volume (1012 km3) 1,412,000. 1.083 1,304,000. Volumetric mean radius (km) 695,700. 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) 0.070 0.3308 0.212 Visual magnitude V(1,0) -26.74 -3.86 - Absolute magnitude +4.83 Luminosity (1024 J/s) 382.8 Mass conversion rate (106 kg/s) 4260. Mean energy production (10-3 J/kg s) 0.1925 Surface emission (106 J/m2s) 62.94 Spectral type G2 V

Model values at center of Sun: Central pressure: 2.477 x 10 11 bar Central temperature: 1.571 x 10 7 K Central density: 1.622 x 10 5 kg/m 3

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 23.44 0.309 Speed relative to nearby stars (km/s) 19.4

2

4

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 (10 6 km) 149.6 Minimum (10 6 km) 147.1 Maximum (10 6 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: 5772 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

Author/Curator:

Dr. David R. Williams, dave.williams@nasa.gov

NSSDCA, Mail Code 690.1

NASA Goddard Space Flight Center

Greenbelt, MD 20771

+1-301-286-1258



NASA Official: Ed Grayzeck, edwin.j.grayzeck@nasa.gov

Last Updated: 23 February 2018, DRW