Astro Note 18: Basic Astronomical Data

Solar System

 
Mean Distance from Sun
Sidereal
Diameter at
       
Planet A.U. Miles Year Equator Mass Gravity Rotation # of
    (mil-lions)   (Miles) (Earth
=1)
(Earth
=1)
(Days) Mo-ons
Sun       864,049 332946 27.9 25-35*  
Mercury 0.387 35.9 87.97d 2,160 0.0553 0.38 58.65 0
Venus 0.723 67.0 224.7d 7,500 0.815 0.91 243 0
Earth 1.000 92.8 365.26d 7,937 1.000 1.00 1 1
Mars 1.524 141 687d 4,220 0.107 0.38 1.03 2
Jupiter 5.203 483 11.86y 88,850 317.9 2.54 0.41* 16
Saturn 9.529 884 29.5y 74,900 95.18 1.08 0.44 18
Uranus 19.23 1785 84 y 31,800 14.54 0.91 0.72 15
Neptune 30.14 2800 164.8y 30,800 17.15 1.19 0.67 8
Pluto 39.81 3700 247.7y 1,430 0.002 0.06 6.39 1

* depends on latitude, equatorial period given

Additional Earth Data

Equatorial Diameter: 7937 miles
Polar Diameter: 7900 miles
1 degree of latitude or longitude: 69 miles at the equator, less closer to poles
Magnetic North Pole: N76°, W101° -- (near Prince of Wales Isl., NWT, Canada)
Magnetic South Pole: S66°, E140° -- (near Antarctic coast, south of Australia)
Orbital Speed: 18.5 miles/sec

Solar Data

Mass: 2 x 1030 kg (2.2 x 1027 tons)
Power Output: 3.8 x 1023 kW
Energy Flux at Earth's Orbital Distance: 1.37 kW/meter2
Solar Wind Speed near Earth: 280 miles/sec
Solar Velocity: 12.3 miles/sec -- (toward R.A. = 18.1h, dec. = +30°; E. Hercules)

Stars within 10 Light Years of the Sun

Name Right Ascension Declination distance
(light years)
Proxima 14h 30m -62° 41' 4.2
a Centauri 14h 40m -62° 50' 4.3
Barnard's 17h 58m +04° 34' 6.0
Wolf 359 10h 56m +07° 01' 7.7
BD+36 2147 11h 03m +35° 59' 8.3
L-726-A/B 01h 39m -17° 57' 8.4
Sirius 06h 45m -16° 43' 8.6
(a CMj) 06h 45m -16° 43' 8.6
Ross 154 18h 50m -23° 50' 9.4

Milky Way Galaxy

Mass: 1012 solar masses
Center: Direction: a = 17.8h, d = -29° (in Sagittarius)
Center: Distance: 29,000 lt. yrs.
Diameter: 90,000 ly
Velocity: 370 miles/sec relative to 3°K background radiation toward a = 10h, d = -20° (southeast Hydra)

Some Close Galaxies of the Local Group

Name Right Ascension Declination distance
(light years)
Large Magellanic Cloud 05h 24m -69° 45' 163,000
Small Magellanic Cloud 00h 53m -72° 49' 196,000
Leo I 10h 09m +12° 14' 750,000
Leo II 11h 14m +22° 09' 750,000
M31, M32 00h 42m +41° 00' 2.3 million
M33 01h 34m +30° 39' 2.4 million

Most Distant Object Readily Visible in an Amateur Telescope

Quasar 3C273 (position: R.A. = 12h 29m, dec. = +02° 03') approximately 2 - 3 billion light years (typically requires 10-inch or larger telescope)

Compiled from a variety of sources and may not maintain consistent basis for various data items. All coordinates are J2000.