Back to the article index

## Physical Constants

The following table comes from Astrophysical Formulae by Kenneth R. Lang, California Institute of Technology, Pasadena, California and Tufts University, Medford, Massachussetts.

 Symbol Meaning Value c Speed of light in vacuum 2.997924562(11) x 1010 cm sec-1 h = 2 Planck's constant 6.626196(50) x 10-27 erg s = h / 2 Rationalized Planck's constant 1.0545919(80) x 10-27 erg s k Boltzmann's constant 1.380622(59) x 10-16 erg K-1 e Elementary charge of an electron 4.803250(21) x 10-10 ESU me Rest mass of the electron 9.109558(54) x 10-28 g G Gravitational constant 6.6732(31) x 10-8 dyne cm2 g-2 NA Avogadro's number 6.022169(40) x 1023 mole-1 a.m.u. = u Atomic mass unit 1.660531(11) x 10-24 g Fine-structure constant 7.297351(11) x 10-3 e / m Electron charge-to-mass ratio 5.272759(16) x 1017 esu g-1 R Rydberg constant 1.09737312(11) x 105 cm-1 a0 Bohr radius 5.2917715(81) x 10-9 cm h / (mc) Compton wavelength 2.4263096(74) x 10-10 cm r0 = e2 / (mc2) Classical electron radius 2.817939(13) x 10-13 cm R Gas constant 8.31434(35) x 107 erg K-1 mole-1 Stefan-Boltzmann constant 5.66961(96) x 10-5 erg cm-2 s-1 K-4 T Thomson cross section 6.652453(62) x 10-25 cm2 au Astronomical unit 1.49597892(1) x 1013 cm pc Parsec 3.0856(1) x 1018 cm ly Light year 9.4605 x 1017 cm = 6.324 x 104 au M Solar mass 1.989(2) x 1033 g R Solar radius 6.9598(7) x 1010 cm L Solar luminosity 3.826(8) x 1033 erg sec-1 eV Electron volt   associated wavelength   associated wavenumber   associated frequency   associated energy   associated temperature 1.23963 x 10-4 cm 8.0671 x 103 cm-1 2.41838 x 1014 Hz 1.60184 x 10-12 erg 1.16059 x 104 °K