Clight = 2.99792458e10;
Ggrav = 6.674215e-8;
Hplanck = 6.6260755e-27;
Echarge = 4.8032068e-10;
Me = 9.1093898e-28;
Mp = 1.6726231e-24;
Mn = 1.6749286e-24;
Kb = 1.380658e-16;
Nav = 6.0221367e23;
SigmaBlack = 5.67051e-5;
SigmaT = 8*pi/3 *(Echarge^2/(Me* Clight^2))^2; 
Ablack = 7.56591e-15;
EV = 1.60217733e-12;
MEV = 1e6*EV; 
Lsun = 3.847e33;
Msun = 1.9891e33;
Mjup = 1.9e30; 
Rsun = 6.96e10;
Rjup = 1.42800e10;
Teffsun = 5780;
Year=365.25*24*3600;
Pc = 3.086e18;
Mpc = 1e6*Pc; 
Au = 1.496e13;
Amu = 1.66057e-24;

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-13.6*EV/Clight^2;
Arcsec = Au/Pc;
Mas = Arcsec*1e-6; 
Degree = 2*pi/360; 
Arcmin = 60*Arcsec; 
Myr = 1e6*Year; 
Kps = 1e5;
Km = 1e5;