Useful constants and equations

Constants

G = 6.6726á 10-11 N m2 / kg2                      s = 5.6705 á 10-8 W m-2 K-4

c = 3 á108 m s-1                                             g = 9.8 m s-2

1 A.U.= 150 á106 km                                   h = 6.626 á10-34 J s

LSun = 3.9 á 1026 W                                        1 ly = 9.46 á 1012  km           

M Earth = 5.974 á 1024 kg                               R Earth = 6378 km

1 pc = 3.26 ly                                                         LSun = 3.90 á 1026 W

RSun = 6.96 á 105 km                                   MSun = 1.989 á 1030 kg

 

Equations

F = m a                                                                       F = G m1 m2 / r2

P2 = k a3

P2 = 4 p2 a3/ [G (m1 + m2)]

Area (ellipse) = p a b                                                         

Perihelion = a (1 – e)                                              Aphelion = a (1 + e)

Dl / l0 = v / c                                                             Dl = l - l0

1 / S = 1 / P – 1 / E                                                   1 / S = 1 / E - 1 / P

 q = v / c                                                                      D = a d/206,265

d = 206,265 / p                                                        

g = G Mearth / R2earth                                                   v2esc  = 2 g Rearth

q = 2.5 105  á  l / D                                                    r = M / V

lmax = 0.0029 / T                                                      E = h n

F = s T4                                                                                             L = F A

Circumference (circle) = 2 p R                              Area (sphere),  A= 4 p R2

                                                                                    Volume (sphere), V = (4/3) p R3

m - M = -5 + 5 log (d)                                               m2 - m1 = 2.5 log (b1/b2)