Clight = 2.99792458 10^10 cm/s Ggrav = 6.6726 10^-8 erg cm/g^2 Hplanck = 6.6260755 10^-27 erg s Echarge = 4.8032068 10^-10 erg^(1/2) cm^(1/2) Me = 9.1093898 10^-28 g Mp = 1.6726231 10^-24 g; Alphafs = Echarge^2 /(Hbar Clight) Rbohr = Hbar^2 /(Me Echarge^2) Rydberg = Me Echarge^4 /(2 Hbar^2) Rgas = Nav Kb; Mh = Mp+Me-13.6EV/Clight^2; Arcsec = Au/Pc; Mas = Arcsec 10^-6; Arcmin= 60 Arcsec; Rearth = 5800 Km; Km = 10^5 cm; Kps = Km; Kb = 1.380658 10^-16 erg; (* Chandrasekhar mass. Requires mue. 1.4 when mue=2. *) Mchandra := (0.19670190901523182*Clight^(3/2)*Hplanck^(3/2))/(Ggrav^(3/2)*Mh^2*mue^2); Mchandra14 := (0.19670190901523182*Clight^(3/2)*Hplanck^(3/2))/(Ggrav^(3/2)*Mh^2*2^2); Alpha2 = 3.46*^-13 cm^3 s^-1; (* Recombination rate coefficient *) erg := g cm^2/s^2 Sigmablack = Clight Ablack / 4 ; Ablack = Kb^4 8 Pi^5/(15 Clight^3 Hplanck^3) SigmaT = 8Pi/3 (Echarge^2/(Me Clight^2))^2 EV = 1.60217733 10^-12 erg Lsun = 3.847 10^33 erg/s Msun = 1.9891 10^33 g Rsun = 6.96 10^10 cm Teffsun = 5780 Hour = 3600 s; Day = 24 Hour; Year=365.25 Day; Myr = 10^6 Year Pc = 3.086 10^18 cm Au = 1.495979 10^13 cm ; Angstrom = 1*^-8 cm ; (* from Kittel -- maybe old numbers. *) Amu = 1.66057 10^-24 g ; (*derivative quantities*) Kpc = 1*^3 Pc; Mpc = 1*^6 Pc; Hbar = Hplanck/(2 Pi) Reclass = Echarge^2 /(Me Clight^2) Recompton = Hbar/(Me Clight) Alphafs = Echarge^2 /(Hbar Clight) Rbohr = Hbar^2 /(Me Echarge^2) Rydberg = Me Echarge^4 /(2 Hbar^2) Rgas = Nav Kb; Mh = Mp+Me-13.6EV/Clight^2; Arcsec = Au/Pc; Mas = Arcsec 10^-6; Arcmin= 60 Arcsec; Rearth = 5800 Km; Km = 10^5 cm ; Kps = Km/s;