Astronomical Constants & Approximations
Astronomical Approximations
| 1 year
| pi · 107 sec
| 3.15576 · 107 sec
|
| 1 mas
| 5 · 10-9 radians
| 4.848136811 · 10-9 radians
|
| 1 mas/yr
| 4.74 km/s/kpc
| 4.7405049 km/s/kpc
|
| 1 pc/Myr
| 1 km/s
| 0.9778 km/s
|
| 1 °
| 1.75 pc (at a distance of 100 pc)
|
| 1 mas/yr
| 0.5 km/s (at a distance of 100 pc)
|
| 50 km/s/Mpc
| 0.18 µas/a
| Hubble constant H0
|
Astronomical Constants
| 1 pc
| 3.0857 · 1016 m = 2 · 105 AU = 3.26 ly
|
| 1 AU
| 1.49597870 · 1011 m = 215 RSun
|
| 1 MSun
| 1.9891 · 1030 kg = 1047 MJup
|
| 1 RSun
| 6.96 · 108 m
|
| 1 LSun
| 3.9 · 1026 W
|
| 1 Mbol,Sun
| 4.72 mag
|
| 1 MJup
| 1.90 · 1027 kg = 318 MEarth
|
| 1 MEarth
| 5.976 · 1024 kg
|
Physical Constants
| c
| 2.99792458 · 108 m/s
|
| G
| 6.6720 · 10-11 m3/kg/s2
= 0.0043 pc/MSun (km/s)2
|
| |
= (2 · pi)2 (AU)3/(MSun yr2)
|
| h
| 6.626 · 10-34 Js
|
| e
| 1.6021892 · 10-19 C
|
| me
| 9.1095 · 10-31 kg
|
| k
| 1.380662 · 10-23 J/K
|
| sigma
| 5.67032 · 10-8 W/m2/K4
|
Other Helpful Numbers
| pi
| 3.1415926535897932...
|
|
| 41 252 sqare degree
| area of the entire sky
|
