IAU Rec. | VizieR symbol | VizieR explanation | VizieR SI value | HEASARC symbol | GNU expression | GNU aliases | Note | |
% | percent | 0.01 | percent | % | ||||
A | A | Ampere | A | A | A | ampere, amp | ||
a | a | year | 3.15576×10+7s | see yr | ||||
a0 | (Bohr radius) | 5.29177×10-11m | bohrradius | atomiclength | ||||
al | light-year | 9.46053×10+15m | lightyear | ly | ||||
alpha | (fine structure constant) | 7.29735×10-3 | alpha | |||||
Å ‡ | Angstrom | ?Angstroem(0.1nm) | 10-10m | angstrom | angstrom | ångström, Å | ||
Å | ?Angstroem(0.1nm) | 10-10m | see Angstrom | |||||
' | arcmin | minute of arc | 4.62963×10-5 | arcmin | arcmin | arcminute, ' | ||
" | arcsec | second of arc | 7.71605×10-7 | arcsec | arcsec | arcsecond, " | ||
atm ‡ | atm | ?atmosphere | 1.01325×10+5Pa (kg·m-1·s-2) | atm | atmosphere | |||
AU | astronomical unit | 1.49598×10+11m | AU | see au | ||||
au | au | astronomical unit | 1.49598×10+11m | astronomicalunit | au | |||
bar ‡ | bar | ?bar(10+5Pa) | 10+5Pa (kg·m-1·s-2) | bar | ||||
b ‡ | barn | barn(10-28m2) | 10-28m+2 | barn | barn | |||
bit | binary information unit |
| bit | |||||
byte | byte(8bits) |
| byte | byte | B | |||
C | C | Coulomb | C (s·A) | C | coulomb | C | ||
c | c(speed_of_light) | 2.99792×10+8m·s-1 | c | light | ||||
cal ‡ | cal | ?calorie | 4.1854J (kg·m+2·s-2) | cal_IT | cal, calorie, calorie_IT | 1 | ||
cd | cd | candela(lumen/sr) | cd | cd | cd | candela | ||
ct | count |
| count | ??? | ||||
D | Debye (dipole) | 3.33333×10-30m·s·A | debye | |||||
d | d | day | 8.64×10+4s | d | day | d, da | ||
o | deg | degree | 2.77778×10-3 | deg | degree | arcdeg | ||
oC | degC | Celsius | K | degC | degcelsius | |||
degF | ?Fahrenheit | 5.55556×10-1K | degF | degfahrenheit | ||||
dyn ‡ | dyn | ?dyne(10-5N) | 10-5N (kg·m·s-2) | dyne | dyn | |||
e | e(electron_charge) | 1.60218×10-19C (s·A) | e | |||||
eps0 | (electric constant) | 8.85419×10-12kg-1·m-3·s+4·A+2 | epsilon0 | |||||
erg ‡ | erg | ?erg(10-7J) | 10-7J (kg·m+2·s-2) | erg | erg | |||
eV | eV | electron-Volt | 1.60218×10-19J (kg·m+2·s-2) | eV | eV | electronvolt, ev | ||
F | F | Farad | F (kg-1·m-2·s+4·A+2) | F | farad | F | ||
G | G(gravitation constant) | 6.673×10-11kg-1·m+3·s-2 | G | |||||
g | gram | 10-3kg | gram | gm, g, gramme | ||||
G ‡ | gauss | ?Gauss(10-4T) | 10-4T (kg·s-2·A-1) | G | gauss | Gs | 2 | |
geoMass | Earth mass | 5.976×10+24kg | earthmass | |||||
H | H | Henry | H (kg·m+2·s-2·A-2) | H | henry | H | ||
h | h | hour | 3.6×10+3s | h | see hr | 3 | ||
hr | ?hour(use 'h') | 3.6×10+3s | hour | hr | ||||
\h | hbar(Planck constant) | 1.05457×10-34kg·m+2·s-1 | hbar | spin, atomicaction | ||||
Hz | Hz | Herz | Hz (s-1) | Hz | Hz | hz | ||
inch | ?inch | 2.54×10-2m | inch | in | ||||
J | J | Joule | J (kg·m+2·s-2) | J | joule | J | ||
JD | Julian Day | 8.64×10+4s | ??? | |||||
jovMass | Jupiter mass | 1.902×10+27kg | jupitermass | |||||
Jy | Jy | Jansky(10-26W/m2/Hz) | 10-26kg·s-2 | Jy | fluxunit | jansky, Jy | ||
K | K | Kelvin | K | K | K | kelvin | ||
k | k(Boltzmann) | 1.38065×10-23kg·m+2·s-2·K-1 | boltzmann | k | ||||
kg | kg | kilogram | kg | kg | kg | kilogram | ||
l | ?litre | 10-3m+3 | liter | l, litre | ||||
lm | lm | lumen | 7.95775×10-2cd | lm | lumen | lm | ||
lx | lx | lux(lm/m2) | 7.95775×10-2m-2·cd | lx | lux | lx | ||
lyr | ?light-year (c*yr) | 9.46053×10+15m | lyr | see al | ||||
m | m | metre | m | m | m | meter, metre | ||
mag † | mag | magnitude | mag | mag | ??? | |||
mas † | mas | milli-second of arc | 7.71605×10-10 | mas | ||||
me | me(electron_mass) | 9.10938×10-31kg | electronmass | m_e | ||||
min | min | minute | 6×10+1s | min | minute | min | ||
MJD | Mod. Julian Date (JD-2400000.5) | 8.64×10+4s | ??? | |||||
mmHg | ?mercury_mm | 1.33322×10+2Pa (kg·m-1·s-2) | mmHg | torr | ||||
mol | mol | mole | mol | mol | mol | mole | ||
month | ?month |
| month | mo | ||||
mp | mp(proton_mass) | 1.67266×10-27kg | protonmass | m_p | ||||
mu0 | (magnetic constant) | 1.25664×10-6kg·m·s-2·A-2 | mu0 | |||||
muB | (Bohr magneton) | 9.27401×10-28m+2·A | bohrmagneton | mu_B | ||||
N | N | Newton | N (kg·m·s-2) | N | newton | N | ||
Ω | Ohm | Ohm(V/A) | Ohm (kg·m+2·s-3·A-2) | ohm | ohm | |||
Pa | Pa | Pascal | Pa (kg·m-1·s-2) | Pa | pascal | Pa | ||
pc | pc | parsec | 3.0857×10+16m | pc | parsec | pc | ||
ph | photon |
| photon | ??? | ||||
pi | pi( | 3.14159 | pi | |||||
pix | pixel |
| pixel | ??? | ||||
R | R(gas_constant) | 8.3143kg·m+2·s-2·K-1·mol-1 | gasconstant | R | ||||
rad | rad | radian | 1.59155×10-1 | rad | radian | 4 | ||
Ry | Rydberg(13.6eV) | 2.17989×10-18J (kg·m+2·s-2) | rydberg | |||||
S | S | Siemens(A/V) | S (kg-1·m-2·s+3·A+2) | S | siemens | S, mho | ||
s | s | second | s | s | s | second, sec | ||
sec | ?second (use 's') | s | see s | |||||
solLum | solar luminosity | 3.826×10+26W (kg·m+2·s-3) | ??? | 5 | ||||
Mo | solMass | solar mass | 1.989×10+30kg | solarmass | sunmass | |||
solRad | solar radius | 6.9599×10+8m | sunradius | |||||
sr | sr | steradian | 7.95775×10-2 | sr | sr | steradian | ||
Sun | Solar unit |
| ??? | |||||
T | T | Tesla | T (kg·s-2·A-1) | T | tesla | T | ||
t | ?ton | 10+3kg | tonne | t, metricton | ||||
u | u | atomic mass unit | 1.66054×10-27kg | atomicmassunit | u, amu | |||
uas | micro-second of arc | 7.71605×10-13 | ??? | |||||
V | V | Volt | V (kg·m+2·s-3·A-1) | V | volt | V | ||
W | W | Watt | W (kg·m+2·s-3) | W | watt | W | ||
Wb | Wb | Weber(V·s) | Wb (kg·m+2·s-2·A-1) | Wb | weber | Wb | ||
yr | year | 3.15576×10+7s | yr | tropicalyear | year, yr | |||
µ0 | (magnetic constant) | 1.25664×10-6kg·m·s-2·A-2 | see mu0 | |||||
µas | micro-second of arc | 7.71605×10-13 | see uas | |||||
IAU | http://www.iau.org/Units.234.0.html?&0 | |||||||
VizieR old | http://vizier.u-strasbg.fr/doc/catstd-3.2.htx | |||||||
VizieR cgi | http://vizier.u-strasbg.fr/cgi-bin/Unit?%3f | |||||||
GNU Units | http://www.gnu.org/software/units/ | |||||||
HEASARC | http://heasarc.nasa.gov/docs/journal/units4.html | |||||||
1 | Slightly ambiguous definition of cal... | |||||||
2 | Gs ambiguous | |||||||
3 | h is Planck constant in GNU | |||||||
4 | rad is a radioactive unit in GNU | |||||||
5 | sunlum in GNU is luminance on earth | |||||||
† = discussed in text | ||||||||
‡ = deprecated |