"""Useful constants."""
# flake8: noqa
# internal modules

# external modules

# relative modules

# global attributes
__filename__ = __file__.split('/')[-1].strip('.py')
__path__ = __file__.strip('.py').strip(__filename__)

# %&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&
# CGS PHYSICAL CONSTANTS
# %&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&
c    = 2.99792458e10      # speed of light CGS
h    = 6.6260755e-27      # Planck's constant CGS
g    = 6.67259e-8         # Grav const CGS
kb   = 1.38064852e-16       # Boltzmann's const CGS
a    = 7.56591e-15        # Radiation constant CGS
sb   = 5.67051e-5         # sigma (stefan-boltzmann const) CGS
qe   =  4.803206e-10      # Charge of electron CGS
ev   =  1.60217733e-12    # Electron volt CGS
na   =  6.0221367e23      # Avagadro's Number
me   =  9.1093897e-28     # electron mass CGS
mp   =  1.6726231e-24     # proton mass CGS
mh2  = 3.3476e-24         # molecular hydrogen mass
mn   = 1.674929e-24       # neutron mass CGS
mh   = 1.673534e-24       # hydrogen mass CGS
amu  =  1.6605402e-24     # atomic mass unit CGS
pi   = 3.1415926535897932384626433832795028841
hour = 3.6e3              # s
day  = 8.64e4             # s
year = 3.1557600e7        # s

# %&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&
# ASTRONOMICAL CONSTANTS
# %&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&
# GENERAL
au      = 1.4959787066e13   # astronomical unit CGS
pc      = 3.0857e18         # parsec CGS
yr      = 3.155815e7        # sidereal year CGS
msun    = 1.98900e+33       # solar mass CGS
rsun    = 6.9599e10         # sun's radius CGS
lsun    = 3.839e33          # sun's luminosity CGS
msolsys = 1.00134198 * msun # solar system mas in CGS
mmoon   = 7.35000e+25       # moon mass CGS
mearth  = 5.97400e+27       # earth mass CGS
rmoon   = 1.738e8           # moon radius CGS
rearth  = 6.378137e8        # earth's radius CGS
medd    = 3.60271e+34       # Eddington mass CGS
j2000   = 2451545           # Julian date start j2000
kzen    = 0.17              # typical zenith extinction
kepler  = 7.495E-6          # [AU^3/day^2/Msun] kepler's constant

# %&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&
# ASTRONOMICAL CONSTANTS
# %&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&%&
# North galactic pole (J2000) -- according to Wikipedia
pole_ra  = 192.859508
pole_dec = 27.128336
posangle = 122.932-90.0
# North galactic pole (B1950)
#pole_ra  = 192.25
#pole_dec = 27.4
#posangle = 123.0-90.0

# RADIO SPECIFIC
jy = 1.e-23                  # Jansky CGS
restfreq_hi = 1420405751.786 # 21cm transition (Hz)
restfreq_co = 115271201800.  # CO J=1-0 (Hz)
cm2perkkms_hi = 1.823e18     # HI column per intensity (thin)

# abundances
abun_ratio_c18o_c17o = 4.16
abun_ratio_c18o_h2= 1.7E-7
abun_ratio_c17o_co = 1./1700.
abun_ratio_co_h2 = 10**-4
abun_ratio_h13cop_h2 = 1.72E-11

# end of file
