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Physical and Astronomical Constants

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Units

1 Dyn = 10 micronewtons
1 erg = 0.1 microjoules
1 Jansky = 10**-26 watts per metre square per hertz
1 Angstrom = 0.1 nanometres
1 Megaton = 4*10**15 Joules

An AB magnitude is calculated by the equation

AB=-2.5 log10(flux) - 48.60

Where flux is per unit frequency in erg/cm2/2/Hz. From Oke and Gunn 1983.

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Astronomical Quantities

Wavelength of H-alpha = 6562.8 Angstroms
1 Astronomical unit = 1.4960 times 10**11 m
1 Parsec = 3.0857 times 10**16 m
Mass of Sun = 1.989 times 10**30 kg
Radius of Sun = 6.96 times 10**8 m
Solar Luminosity = 3.8 times 10**26 W
Mass of the Earth = 5.976 times 10**24 kg
Mass of Jupiter = 318 times mass of Earth
Solar constant = 1.37 kW per metre

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Physical Constants

c= 3 times 10**8 metres per second
Mass of Proton = 1.67 times 10**-27 kg
Mass of Proton = 1836.1 times mass of electron
h = 6.62 times 10**-34 Js
e = 1.602 times 10**-19 C
Avogadro's number = 6 times 10**23 per mole
G = 6.67 times 10**-11 N m**2 kg**-2
k = 1.38 times 10**-23 J K**-1
Stefan Boltzmann constant = 5.67 times 10**-8 W m**-2 K**-4
Square degrees on a sphere = 41253

Last Modified: 12th March 2003
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