solsys

Description

Displays description of solar system structures (Sun, Earth, Moon, Mars, Phobos, Deimos) or a description of a field in those structures

This is a user-defined function from constants.dvrc

Arguments and Return Values

Arguments: A string with the name of the structure or field for which a description is needed

Return Value: When given the name of one of the solar system structures, prints description of each element of the structure (but returns zero). When given the name of one of the fields in the structures, returns a string with the description of the field.

If no arguments are input, solsys() prints its description, as shown below.

Usage

Syntax: solsys("field") or solsys("structure")

Examples

dv> Mars
struct, 18 elements
    M: 6.41850e+23
    R: 3.38950e+06
    rho: 3933.00
    aB: 0.250000
    aV: 0.150000
    H: -1.52000
    tr: 30000.0
    kI: 0.366000
    a: 2.27920e+11
    yr: 5.93551e+07
    e: 0.0935000
    srp: 88642.4
    day: 88774.9
    eps: 25.1900
    P: 636.000
    rhoa: 0.0200000
    T: 210.000
    mua: 43.3400
dv> solsys()

solsys returns descriptions of solar system planet structures
solsys("fieldname") returns description of the input field
 e.g. solsys("M") returns "Mass (in kilograms)"
solsys("structname") prints a full description of the specified structure
 e.g. solsys("Mars") explains every field in the Mars structure
Input must be a string
Values in SI/mks units, from NASA planetary fact sheets:
http://nssdc.gsfc.nasa.gov/planetary/planetfact.html
S.Marshall 12-10-2007

0
dv> solsys("Mars")

    Mars

    M    =  6.418500e23 kg     Mass
    R    =  3.389500e6 m       Volumetric mean radius
    rho  =  3933 kg/m^3        Mean mass density
    aB   =  0.250000           Bond albedo
    aV   =  0.150000           Visual geometric albedo
    H    =  -1.520000          Absolute visual magnitude
    tr   =  30000 m            Topographic range
    kI   =  0.366000           Moment of inertia coefficient (I/MR^2)
    a    =  2.279200e11 m      Semimajor axis of orbit
    yr   =  5.935510e7 s       Sidereal year (revolution period)
    e    =  0.093500           Orbital eccentricity
    srp  =  88642.398438 s     Sidereal rotation period
    day  =  88774.898438 s     Length of day
    eps  =  25.190001 degrees  Rotation axial tilt
    P    =  636 Pa             Atmospheric pressure at surface
    rhoa =  0.020000 kg/m^3    Density of air at surface
    T    =  210 K              Average surface temperature
    mua  =  43.340000 g/mol    Mean molecular weight of atmospheric air

0
dv> solsys("srp")
"Sidereal day / rotation period (in seconds;
 for the Sun, this is the rotation period at 16 degrees latitude)"
dv> solsys("mua")
"Mean molecular weight/mass of atmospheric air (in grams per mole - NOT SI)"