Astrophysical Links

Some useful links that I use everyday or every time I observe....

ADS

Preprint Server

Bright Supernovae

Astrophysical Constants

look also in:
Physical constants from NIST

Exponent (base 10) of decimal numbers: e n = 10^n . Units are separated by spaces, positive numbers denote powers, all units to the right of the slash are in the denominator (negative powers).

Astronomy

Distances

 1 AU (Astronomical Unit) = 1.496e11 m = 1.496e13 cm
 1 pc (parsec)            = 3.086e16 m = 3.086e18 cm
                          = 206265 AU
                          = 3.26 Light years

Sun

 Radius               6.960e8 m     = 6.960e10 cm
 Mass                 1.989e30 kg   = 1.989e33 g
 Luminosity           3.85e26 W     = 3.85e33 erg
 Surface gravity      2.736e2 m/s2  = 2.736e4 cm/s2
 Temperature          5780 K

 Absolute magnitude   5.72 mag (U)
                      5.54 mag (B)
                      4.87 mag (V)
                      4.74 mag (bolometric)

Magnitudes

   mag1-mag2 = -2.5 log(flux_1/flux_2)

  -(mag1-mag2)    1     2.5   5   10   15   20
 flux_1/flux_2    2.51  10    1e2 1e4  1e6  1e8

  -(mag1-mag2) << 1 :  -(mag1-mag2)+1 = flux_1/flux_2

Absolute calibration of photometry

  Filter lambda   flux density for 0 mag    A/A_v
  band    nm      W/(m^2 hz^1)   W/(nm m^2)

  U       365      1.81e-23      4.22e-11   1.531
  B       440      4.26e-23      6.40e-11   1.324
  V       550      3.63e-23      3.75e-11   1.000
  R       720      2.94e-23*     1.70e-11   0.748
  I       900      2.24e-23*     0.83e-11   0.482
  Rc      640      3.08e-23      2.25e-11*  0.830
  Ic      790      2.55e-23      1.22e-11*  0.628
  J      1250      1.60e-23*     3.07e-12   0.282
  H      1650      1.09e-23*     1.20e-12   0.175
  K      2200      6.49e-24      4.10e-13   0.112
  L      3500      2.61e-24*     6.40e-14   0.058
  M      4800      1.46e-24*     1.90e-14   0.023
  u       350      1.33e-23*     3.25e-11
  v       410      4.03e-23*     7.18e-11
  b       470      4.28e-23*     5.81e-11
  y       550      3.73e-23*     3.70e-11

  (*: calculated from other column; otherwise F_nu and 
   F_lambda from different sources and therefore 
   inconsistent, differences around 5 percent)

Physics

 Gravitational constant G 
          G =  6.6732e-11 m3/kg s2   = 6.6732e-8 cm3/g s2
 Speed of light c  
          c = 2.99792458e8 m/s       = 2.99792458e10 cm/s  
 Planck constant h  
          h = 6.6260755e-34 J s      = 6.6260755e-27 erg s 
   h/(2 pi) = 1.05457266e-34 J s     = 1.05457266e-27 erg s 
 Boltzmann constant k_B  
        k_B = 1.380658e-23 J/K       = 1.380658e-16 erg/K 
 Planck radiation constant c_2  
        c_2 = 1.4338e-2 m K          = 1.4339 cm K 
 Stefan-Boltzmann constant sigma  
      sigma = 5.6705e-8 W/m2 K4      = 5.6705e-5 erg/cm2 s K4
 Gas constant R = N_A k_B 
          R = 8.3143 m2 kg/s2 K mol  = 8.3143 erg/mol K
 Avogadro number N_A  
        N_A = 6.0221367e23 1/mol 
 Elementary charge e  
          e = 1.60217733e-19 C       = 4.8032e-10 E.S.E.
 Atomic mass unit amu 
      1 amu = 1.66057e-27 kg         = 1.66057e-24 g
 Permeability of vacuum mu_0 ( = 4 pi e-7 T2 m3/J)   
       mu_0 = 12.566371e-7 T2 m3/J 
 Permittivity of vacuum epsilon_0 = 1 / (mu_0 c^2) 
  epsilon_0 = 8.854187817e-12 C2/J m 
 Rest masses 
 m_electron = 9.1093897e-31 kg       = 9.1093897e-28 g
 m_proton   = 1.6726231e-27 kg       = 1.6726231e-24 g 
 m_neutron  = 1.6749286e-27 kg       = 1.6749286e-24 g 
 Fine structure constant 1 / alpha  
  1 / alpha =  137.0359895 
 Compton wavelength of the electron lambda_e = h / (m_e c)  
   lambda_e = 2.42631e-12 m          = 2.42631e-10 cm
            = 2.42631e-2 A
 Compton wavelength of the proton lambda_p = h / (m_p c)  
   lambda_p = 1.3214e-15 m           = 1.3214e-13 cm
 Charge-to-mass ratio for electron e / m_e  
    e / m_e = 1.75880e11 C/kg        = 5.2728e17 E.S.E./g
 Electron radius r_e 
        r_e = 2.81792e-15 m          = 2.81792e-13 cm
 Bohr radius a_0 
        a_0 = 5.29177e-11 m          = 5.29177e-9 cm
 Rydberg constant R_inf  
      R_inf = 1.0974e7 1/m           = 1.0974e5 1/cm 
            = 1/911.27 A
 Bohr radius a_0 
        a_0 = 5.29177e-11 m          = 5.29177e-9 cm
 Bohr magneton mu_B = eh/(4 pi m_e) 
       mu_B = 9.2740154e-24 J/T 
 Nuclear magneton mu_N = eh/(4 pi m_p)  
       mu_N = 5.0507866e-27 J/T 
 Free electron g factor  g_e  
        g_e = 2.002319304386 
 Free electron gyromagnetic ratio gamma_e = 2 pi g_e mu_B / h 
    gamma_e = 1.7608592e11 1/s T 
 Electron magnetic moment mu_e = -(1/2) g_e mu_B  
       mu_e = -9.2847701e-24 J/T 
 Proton gyromagnetic ratio (H2O) gamma_p  
    gamma_p = 2.67515255e8 1/s T 
 Proton magnetic moment mu_p 
       mu_p = 1.41060761e-26 J/T 
 Proton-electron ratios 
        m_p/m_e = 1836.152701 
      mu_e/mu_p = 658.2106881 
gamma_e/gamma_p = 658.2275841 (protons in water) 
 Molar volume V_mol 
      V_mol = 22.41383 m3/kmol 
 Faraday constant F = N_A e  
          F = 9.64846e4 C/mol 
 Proton g factor (Lande factor) g_H  
        g_H = 5.585 
 Acceleration due to gravity (Earth) g 
          g = 9.80665 m/s2 
 Atomic energy unit Hartree = e^2 /(4 pi epsilon_0 a_0)  
   1 Hartree = 2.625501e+06 J/mol 
   1 Hartree = 627.5 kcal/mol 
 Proton Larmor frequency nu_p = gamma_p/(2 pi) B 
        nu_p = 42.5764 MHz/T (H2O) 
 Electron Larmor frequency nu_e = gamma_e/(2 pi) g/g_e B 
  nu_e [GHz] = 13.9962 g B[T] 
           g = 0.07144775 nu_e[GHz]/B[T] 
           g = 3.04199 nu_e[GHz]/nu_p[MHz] 
       B [T] = 0.0234872 nu_p[MHz]