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Astronomical Data

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Reference

The inner planets (terrestrial planets) Sources: NASA planetary fact sheet for Mercury, Venus, Earth, Mars
  Mercury Venus Earth Mars
traditional
symbol
mass
(1024 kg)
0.33011 4.8675 5.9723 0.64171
mean radius
(km)
2,439.7 6,051.8 6,371.000 3,389.5
equatorial radius (km) 2,439.7 6,051.8 6,378.137 3,396.2
polar radius
(km)
2,439.7 6,051.8 6,356.752 3,376.2
flattening
factor
0.0000 0.0000 0.003353 0.00589
moment of inertia constant 0.33 0.33 0.3308 0.366
axial tilt
(°)
0.034 177.36 23.44 25.19
semimajor axis
(106 km)
57.91 108.21 149.60 227.92
perihelion
(106 km)
46.00 107.48 147.09 206.62
aphelion
(106 km)
69.82 108.94 152.10 249.23
orbital
eccentricity
0.2056 0.0067 0.0167 0.0935
orbital
inclination
 (°)
7.00 3.39 0
(by definition)
1.850
sidereal
orbit (days)
87.969 224.701 365.256 686.980
tropical
orbit (days)
87.968 224.695 365.242 686.973
sideral period
(hours)
1,407.6 −5,832.5 23.9345 24.6229
length of day
(hours)
4,222.6 2,802.0 24.0000 24.6597
mean surface
pressure (kPa)
10−12 9,200 101.325
(by convention)
0.638
mean surface
temperature (K)
440 737 288 210
blackbody
temperature (K)
442.5 231.7 254.3 210.1
natural
satellites
none none 1 2
planetary
ring system
none none none none
The outer planets (Jovian planets) Sources: NASA planetary fact sheet for Jupiter, Saturn, Uranus, Neptune
  Jupiter Saturn Uranus Neptune
traditional
symbol
mass
(1024 kg)
1,898.19 568.34 86.813 102.413
mean radius
(km)
69,911 58,232 25,362 24,622
equatorial
radius (km)
71,492 60,268 25,559 24,764
polar radius
(km)
66,854 54,364 24,973 24,341
flattening
factor
0.06487 0.09796 0.02293 0.01708
moment of inertia constant 0.254 0.210 0.225
axial tilt
(°)
3.13 26.73 97.77 28.32
semimajor axis
(106 km)
778.57 1,433.53 2,872.46 4,495.06
perihelion
(106 km)
740.52 1,352.55 2,741.30 4,444.45
aphelion
(106 km)
816.62 1,514.50 3,003.62 4,545.67
orbital
eccentricity
0.0489 0.0565 0.0457 0.0113
orbital
inclination
 (°)
1.304 2.485 0.772 1.769
sidereal
orbit (days)
4,332.589 10,759.22 30,685.4 60,189
tropical
orbit (days)
4,330.595 10,746.94 30,588.740 59,799.9
sideral period
(hours)
9.9250 10.656 −17.24 16.11
length of day
(hours)
9.9259 10.656 17.24 16.11
mean surface
pressure (kPa)
n/a n/a n/a n/a
mean surface
temperature (K)
165 134 76 72
blackbody
temperature (K)
110.0 81.1 58.2 46.6
natural
satellites
79 62 27 14
planetary
ring system
1 extensive 13 9
discovery antiquity antiquity William Herschel
13 March 1781
Johann Galle
23 September 1846
Selected minor bodies Sources: JPL small-body database browser for 1 Ceres, 1P/Halley, 136199 Eris; NASA planetary fact sheet for Pluto
  Ceres Halley Pluto Eris
traditional
symbol(s)
family main belt asteroid short period comet kuiper belt object trans-neptunian object
mass
(1024 kg)
0.000938 0.0075 0.01303 ?
mean radius
(km)
469.7 5.5 1,187 1,350
axial tilt
(°)
? ? 122.53 ?
semimajor axis
(106 km)
414.012 2,667.95 5,906.38 10,139.8
perihelion
(106 km)
382.621 87.661 4,436.82 5,671.36
aphelion
(106 km)
445.405 5,248.24 7,375.93 14,608.3
orbital
eccentricity
0.758228 0.967143 0.2488 0.440685
orbital
inclination
 (°)
10.5934 −17.7373 17.16 44.0447
sidereal
orbit (days)
1,681.63 27,509.1 90,560 203,824
tropical
orbit (days)
? ? ? ?
sideral period
(hours)
9.07417 ? −153.2928 25.9
length of day
(hours)
? ? 153.2820 ?
mean surface
pressure (kPa)
? ? 0.0003 ?
mean surface
temperature (K)
167 ? 50 ?
blackbody
temperature (K)
? ? 37.5 ?
natural
satellites
0 0 5 1
discovery Giuseppe Piazzi
1 January 1801
antiquity Clyde Tombaugh
18 February 1930
Brown, Trujillo, Rabinowitz 5 January 2005
The Galilean satellites of Jupiter Source: NASA Jovian satellite fact sheet
  Io Europa Ganymede Callisto
mass
(1022 kg)
8.932 4.800 14.819 10.759
mean radius
(km)
1,821.6 1,560.8 2,631.2 2,410.3
semimajor
axis (km)
421,800 671,100 1,070,400 1,882,700
orbital
eccentricity
0.004 0.009 0.001 0.007
orbital
inclination (°)
0.04 0.47 0.18 0.19
sidereal
orbit (days)
1.769138 3.551181 7.154553 16.689017
discovery Galileo Galilei
7 January 1610
Selected large satellites Sources: NASA planetary fact sheet for moon, Titan, Triton, Charon
  Moon Titan Triton Charon
traditional
symbol(s)
☾ ☽
satellite
of…
earth saturn neptune pluto
mass
(1022 kg)
7.346 13.455 2.14 0.1586
mean radius
(km)
1,737.4 2,575 1,353.4 603.6
semimajor
axis (km)
384,400 1,221,830 354,760 19,596
perigee
(km)
363,300
apogee
(km)
405,500
orbital
eccentricity
0.0549 0.0292 0.000016 0.0002
orbital
inclination (°)
5.145 0.33 157.345 0.00005
sidereal
orbit (days)
27.3217 15.945421 −5.876854 6.3872
mean surface
pressure (kPa)
10−13 150
mean surface
temperature (K)
95–390 95
discovery antiquity Christiaan Huygens
25 March 1655
William Lassell
10 October 1846
James Christy
22 June 1978
Selected stars Sources: I forgot to record them
  sun proxima centauri sirius betelgeuse
traditional
symbol
 
mass 1.989 × 1030 kg  
 
0.12 m  
 
2.14 m 12–17 m
radius 6.960 × 108 m  
 
0.12 r  
 
1.68 r 650 r
luminosity 3.839 × 1026 W  
 
0.0009 L  
 
26.1 L 9400 L
temperature 5,780 K  
 
2,670 K  
 
9,900 K 3,100 K
type G2
(main sequence)
M5
(red dwarf)
A1
(main sequence)
M1
(red supergiant)
distance
from earth
1.496× 1011 m 4.27 light years 8.57 light years 520 light years