Path: SC/Ephem
% Simplified planet ephemerides from the almanac.
Has functions for the orbital elements of the planets in the
heliocentric frame. The elements are row vectors as follows:
a = [ a1 a0] semi-major axis
e = [ e1 e0] eccentricity
i = [ i1 i0] inclination
W = [ W1 W0] longitude of the ascending node
w = [ w1 w0] argument of perigee
L = [L2 L1 L0] mean longitude: L2 is revolutions per century
where
x = b1*T + b0 where T is Julian Centuries from J2000.0
and bi is a coefficient. Output of the angular quantities is
either in degrees or radians.
If one output is specified it will be a data structure containing
the planet information.
Type Planets for a demo. See SolarSys for computing planet locations.
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Form:
Planets; % demo
planetList = Planets; % list of planets
[name, a, e, i, W, w, L, jDRef, mu, m, radius] = Planets( units, k )
d = Planets( units, k ) % output a data structure array
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Inputs
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units (1,3) Angular units ('deg' or 'rad')
k (1,1) or {} Planet IDs, if not input get all nine;
can be a cell array
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Outputs
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name (n,:) Name of planet
a (n,2) Mean distance (au)
e (n,2) Eccentricity
i (n,2) Inclination wrt ecliptic plane (units)
W (n,2) Longitude of ascending node wrt vernal equinox (units)
w (n,2) Argument of perhelion (units)
L (n,3) Mean longitude (units)
jDRef (1,1) Reference Julian date
mu (n,2) Gravitational parameter (km^3/s^2)
m (n,1) Mass (kg)
radius (n,1) Radius (km)
- OR -
d (:) Data structure array with above fields
n is the number of planets
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References: Seidelmann, P. K., ed., Explanatory Supplement to the Astronomical
Almanac, University Science Books, 1992.
Table 5.8.1. p. 316.
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SC: Ephem/SolarSys
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