This is the Web Edition of "A Trip Into Space", a Coimbra-based electronic book on space science. Both the texts and the photos are by courtesy of National Aeronautics and Space Administration.

Pluto Fact Sheet

Pluto/Earth Comparison


Bulk parameters

                                  Pluto          Earth      Ratio (Pluto/Earth)
Mass (1024 kg)                    0.0125         5.9736         0.0021
Volume (1010 km3)                 0.715        108.321          0.0066
Equatorial radius (km)           1195           6378.1        0.187
Polar radius (km)                  1195           6356.8        0.180
Volumetric mean radius (km)        1195           6371.0        0.178         
Ellipticity (Flattening)          0.0000         0.00335        0.0
Mean density (kg/m3)               1750           5515          0.317
Surface gravity (m/s2)            0.58           9.78           0.059
Escape velocity (km/s)            1.1           11.19           0.0983
GM (x 106 km3/s2)                 0.00083        0.3986         0.0021  
Bond albedo                       0.145          0.385          0.377
Visual geometric albedo           0.3            0.367          0.817
Visual magnitude V(1,0)          -1.0           -3.86             -
Solar irradiance (W/m2)           0.89           1367.6         0.0007
Black-body temperature (K)       42.7          247.3            0.1653

Orbital parameters

                                  Pluto           Earth      Ratio (Pluto/Earth)
Semimajor axis (106 km)         5869.66          149.60          39.236
Sidereal orbit period (days)     90,465          365.256        247.68
Tropical orbit period (days)     90,588          365.242        248.02
Perihelion (106 km)             4434.99          147.09          30.152       
Aphelion (106 km)               7304.33          152.10          48.023
Synodic period (days)            366.73             -              -
Mean orbital velocity (km/s)       4.72           29.78           0.158 
Max. orbital velocity (km/s)       6.10           30.29           0.201     
Min. orbital velocity (km/s)       3.71           29.29           0.127    
Orbit inclination (deg)           17.16            0.000           -
Orbit eccentricity                 0.2444          0.0167        14.635
Sidereal rotation period (hrs)  -153.2928         23.9345         6.405
Obliquity to orbit (deg)         122.53           23.45          (2.451)

Pluto Observational Parameters

Discoverer:      Clyde Tombaugh
Discovery Date:  18 February 1930

Distance from Earth
        Minimum (106 km)         4293.7
        Maximum (106 km)         7533.3
Apparent diameter from Earth
        Maximum (seconds of arc)    0.11
        Minimum (seconds of arc)    0.06
Mean values at opposition from Earth
        Distance from Earth (106 km)       5750.54    
        Apparent diameter (seconds of arc)    0.08
        Apparent visual magnitude            15.1      

Pluto Mean Orbital Elements (J2000)

Semimajor axis (AU)                 39.48168677  
Orbital eccentricity                 0.24880766  
Orbital inclination (deg)           17.14175  
Longitude of ascending node (deg)  110.30347  
Longitude of perihelion (deg)      224.06676  
Mean longitude (deg)               238.92881

On 11 February 1999 at 11:22 UT (6:22 a.m. EST), Pluto passed Neptune as the 
furthest planet from the Sun once again and will remain so until 5 April 2231.

Pluto Atmosphere

Surface Pressure: ~3 microbar
Average temperature: ~50 K
Scale height: ~60 km
Mean molecular weight: ~16-25 g/mole
Atmospheric composition:  Methane (CH4), Nitrogen (N2)


Charon

Mean distance from Pluto (km)     19,600        
Sidereal orbit period (days)        6.38725        
Sidereal rotation period (days)     6.38725        
Orbital inclination to Pluto (deg)  0.0       
Orbital eccentricity                0.0
Equatorial radius (km)              593          
Mass (1021 kg)                      1.9        
Mean density (kg/m3)               2000
Surface gravity (m/s2)              0.21
Escape velocity (km/s)              0.58  
Albedo                              0.5
Apparent visual magnitude          16.8

If no sub- or superscripts appear on this page - for example, if the "Mass" is given in units of "(1024 kg)" - you may want to check the notes on the sub- and superscripts.

Last Update: 2004-Nov-27