4(1H) + 2(e-) -- 2He + 2v + 6y
DE=[4(1.007825u)-4.002603u][931 MeV/u]=26.7MeV
mass (kg) = 1989e + 30
radius (km) = 695 000
mean density (gm/cm^3) = 1.410
rotational period (days) = 25-36
escape velocity (km/s) = 618.02
luminosity (ergs/s) = 3.827e33
magnitude (Vo) = -26.8
mean surface temperature = 6000 degrees celsius
age (billions of years) = 4.5
distance from sun (km) = about 150 million
composition
hydrogen - 92.1%
helium - 7.8%
oxygen - 0.061%
carbon - 0.030%
nitrogen - 0.0084%
neon - 0.0076%
iron - 0.0037%
silicon - 0.0031%
magnesium - 0.0024%
sulfur - 0.0015%
all others - 0.0015%
