The symbol index is arranged alphabetically, giving English and then Greek symbols. Astrological symbols appear immediately following the English alphabet. The final portion of the index consists of the most commonly used subscripts. The section and equation numbers appearing in the central column refer to the first use of that symbol. Where one symbol has several distinct usages, each meaning is given with a section reference. For subscripted symbols that do not appear in the main body of the symbol index, the meaning may be determined by looking up the symbol and subscript in the separate portions of the index.

A	Sec. 8.3	Apocenter
A	Sec. 6.4 Eq. (6.4.13)	Variable of substitution
a	Sec. 2.1	Length of semimajor axis
	Sec. 6.4	Point label
	Sec. 7.2	Variable of substitution
B	Sec. 5.3	Magnetic field
BTp	Sec. 19.2	The transplanetary magnetic field (the magnetic field strength in the region of space outside Pluto)
B	Sec. 6.4 Eq. (6.4.14)	Variable of substitution
b	Sec. 4.3	Point label
	Sec. 7.2	Variable of substitution
C	Sec. 2.1 Eqs. (2.1.1)-(2.1.3)	Orbital angular momentum per unit mass

CM	Sec. 2.1	Orbital angular momentum
	Sec. 13.1, Eq. (13.1.1)	Spin angular momentum
c	Sec. 5.3	Velocity of light
	Sec. 6.4	Point label
	Sec. 7.2	Variable of substitution
D	Sec. 6.7, Eq. (6.7.4)	Net transport of guiding centers
d	Sec. 8.3	Point label
	Sec. 21.8	Distance between electrodes
E	Sec. 4.3, Eqs. (4.3.4)-(4 3 5)	Proper eccentricity
	Sec. 5.3	Electric field
	Sec. 9.3	East
Eion	Sec. 21.4.3, Eq. (21.4.4)	The value of the electric field at which discharge and ionization of gas become possible
E||	Sec. 15.3	Electric field parallel to the magnetic field
e	Sec. 2.1	Eccentricity
	Sec. 5.5	2.718 (the base of the natural logarithms)
	Sec. 15.3	Charge on the electron
F	Sec. 17.2, Eq. (17.2.4)	Sum of the gravitational, centrifugal, and electromagnetic forces per unit mass
f	Sec. 3.2	Force per unit mass
fap	Sec. 6.4, Eq. (6.4.3)	Force per unit mass due to apparent attraction to the guiding center of motion
fB	Sec. 17.2	Electromagnetic force per unit mass
fc	Sec. 3.2, Eq. (3.2.2)	Centrifugal force per unit mass
fG	Sec. 3.2	Force per unit mass due to gravitation
fper	Sec. 6.4, Eq. (6.4.4)	Force per unit mass due to a gravitational perturbation
fq	Sec. 5.3	Electromagnetic force per unit mass

ft	Sec. 18.3, Eq. (18.3.2)	Tidal force per unit mass
	Sec. 5.5	Force per unit mass due to impinging energy flux; radiation pressure
G	Sec. 2.1	Universal gravitational constant
g	Sec. 4.3	Absolute visual magnitude
	Sec. 8.2	Acceleration due to Earth's gravitationa field
h	Sec. 2.2	Height above a specified surface
	Sec. 9.2	Height of tides on a celestial body
I	Sec. 4.3, Eqs. (4.3.6)-(4.3.7)	Proper inclination
	Sec. 15.4	Electric current
i	Sec. 2.1	Orbital inclination to the ecliptic plane
ieq	Sec. 2.2	Inclination of equator to the orbital plan.
	Sec. 13.6	Inclination of spin axis to the orbital plane
K	Sec. 11.2, Eq. (11.2.3)	Constant, in cm/g
	Sec. 23.2	Constant, in units of mass
Kr	Sec. 3.3, Eq. (3.3.9)	Constant, in radians
Kz	Sec. 3.3, Eq. (3.3.17)	Constant, in radians
k	Sec. 6.8	Boltzmann's constant
L	Sec. 1.4, Eq. (15.1.1)	Critical hydromagnetic parameter
	Sec. 8.5	Lagrangian points one and two
	Sec. 16.3	Electrostatic double layer
	Fig. 16.3.1
	Sec. 26.3 Eq. (26.3.2)	Latent heat of fusion
L4, L5	Sec. 20.5	Lagrangian points four and five
l	Sec. 8.2	Length of a simple pendulum or the radial distance of a secondary body describing circular motion about a primary body.
	Sec. 15.1	Length (linear extent of medium)

M	Sec. 4.1	Mass of a macroscopic body
MB	Sec. 16.4	Total mass of plasma suspended by the magnetic field at any one given time
MH2O	Sec. 26.4, Eq. (26.4.2)	Mass of water released by impacting planetesimals
Mj	Sec. 12.5	Mass of a jet stream
m	Sec. 5.4	Mass of a small particle or grain
ma	Sec. 11.2	Mass of an atom
me	Sec. 21.9	Mass of the electron
mH	Sec. 11.2	Mass of the hydrogen atom
mper	Sec. 6.4, Eq. (6.4.4)	Small mass introducing a perturbative gravitational force
N	Sec. 4.3	Number function
	Sec. 9.3	North
N	Sec. 6.7	Number density
n	Sec. 2.2	Index of numeration
	Sec. 3.3 Eq. (3.3.15)	The integers
O	Sec. 4.3	The center or origin of motion
P	Sec. 8.3	Pericenter
PB	Sec. 15.1	Magnetic permeability
P0	Sec. 4.3, Eq. (4.3-6)	Forced oscillation
p	Sec. 4.3	Albedo
p0	Sec. 4.3, Eq. (4.3.4)	Forced oscillation
Q	Sec. 9.2	An inverse function of the angle which a tidal bulge makes with respect to the tide-producing body
	Sec. 16.3	Charge passing through a circuit during a given interval of time

Q0	Sec. 4.3, Eq. (4.3.7)	Forced oscillation
q	Sec. 2.5	Ratio of the orbital distances of the innermost and outermost orbiting bodies in one group of secondary bodies
	Sec. 5.3	Electric charge
qn	Sec. 2.2	Ratio of the orbital distances of adjacent secondary bodies
q0	Sec. 4.3, Eq. (4.3.5)	Forced oscillation
R	Sec. 2.2	Radius of a solid body
RG	Sec. 12.3, Eq. (12.3.4)	Radius of growing embryo at transition point between nongravitational accretion and gravitational accretion
	Sec. 2.2	Radius of gyration; inertial radius
r	Sec. 2.4	Orbital radius
	Sec. 3.2	Radial direction
rB	Sec. 23.2, Eq. (23.2.2)	Distance from the central body to a point on a magnetic field line from the dipole magnetic field of that body
rion	Sec. 21.4, Eq. (21.4.1)	Ionization distance (radial distance at which infalling matter can become ionized)
rL	Sec. 11.2, Eq. (11.2.4)	Distance from a secondary body to its interior or exterior Lagrangian points one and two
rmin	Sec. 23.9, Eq. (23.9.6)	Minimum value of orbital radius of condensed matter which is in orbit around the primary body
rMR	Sec. 18.3	The Modified Roche Limit (the radial distance at which matter orbiting a primary body cammot accrete to form a secondary body due to the tidal force of the primary)
rorb	Sec. 2.1	Radial distance from primary body to orbiting secondary body

rper	Sec. 6.4, Eq. (6.4.4)	Radial distance of the perturbing mass mper from the guiding center of motion of another mass.
rR	Sec. 18.3	The Roche limit (the radial distance at which the tidal force of the primary exceeds the self-gravitational force of the secondary)
rrel	Sec. 21.13.3	Orbital distance at which ionization can take place for matter falling through a corotating plasma
rs	Sec. 17.2, Eq. (17.2.13)	Radius of the surface which is the demarcation for plasma falling in toward the central body or falling into the equatorial plane
rsyn	Sec. 23.9	Orbital radius of a synchronous satellite; i.e., a satellite revolving with orbital velocity equal to the rotational velocity of its primary
rTp	Sec. 19.2, Eq. (19.2.2)	The maximum radial distance at which angular momentum transfer from the Sun has ever occurred; furthest extension of the transplanetary magnetic field.
S	Sec. 6.4, Eq. (6.4.3)	Displacement from the guiding center of motion of the particle executing that motion
	Sec. 9.3	South
s	Sec. 16.3	Arc length
T	Sec. 2.1	Sidereal period of revolution
Te	Sec. 5.5, Eq. (5.5.10)	e-folding time (the time in which the value of a given parameter changes by a factor of e (2.718))
Tgy	Sec. 5.4	Period of gyration
Tgz	Sec. 2.2	Sidereal period of revolution of a grazing satellite; i.e., a secondary body having an orbit of semimajor axis equal to the radius of the primary body
Tion	Sec. 23.1	Orbital period of a body orbiting at the ionization distance rion

	Sec. 4.3	Period of variation in the proper elements of asteroid orbital motion
T	Sec. 6.8	Temperature
Te	Sec. 17.3	Electron temperature
Ti	Sec. 17.3	Ion temperature
t	Sec. 3.3	Time
ta	Sec. 12.3	Time of accretion (time at which an accreting embryo would attain an infinite radius)
tc	Sec. 12.6, Eq. (12.6.6)	Time of catastrophic increase of an accreting embryo
tes	Sec. 2.2 Eq. (2.2.3)	"Time of escape" (the ratio of the radius of a body to its escape velocity)
tI	Sec. 16.3, Eq. (16.3.5)	Duration of a current flow
tinf	Sec. 12.4	Infall time (duration of infall of matter into the solar system)
tj	Sec. 12.5, Eq. (12.5.8)	Time at which the small radius of a contracting jet stream would reach zero
tres	Sec. 16.5	Residence time (the interval in which matter resides in the plasma state)
tv	Sec. 6.8	Time between occurrence of collisions; inverse of collision frequency
U	Sec. 12.2, Eq. (12.2.3)	Volume of a toroidal jet stream
u	Sec. 6.8	Relative velocity; "internal velocity" of a jet stream
V	Sec. 5.4	Electrostatic potential; voltage
vb	Sec. 21.8	Burning voltage
VIon	Sec. 15.3	Ionization voltage
v	Sec. 5.5	Velocity
vcrit	Sec. 15.3, Eq. (15.3.1)	Critical velocity at which an infalling atom can become ionized
	Sec. 21.8	The experimental value of relative velocity of a plasma and a gas at which increased ionization occurs.

ves	Sec. 2.2, Eq. (2.2.2)	Escape velocity
vimp	Sec. 12.10, Eq. (12.10.1)	Impact velocity
vion	Sec. 21.4, Eq. (21.4.1)	The value of infall velocity at which ionization of infalling matter can take place
vm	Sec. 12.12, Eq. (12.12.1)	Velocity capable of imparting sufficient kinetic energy to melt a specified mass
vorb	Sec. 2.1	Orbital velocity of secondary body
vrel	Sec. 21.13, Eq. (21.13.3)	Relative velocity
W	Sec. 8.2	Energy (potential and/or kinetic)
	Sec. 9.3	West
Wm	Sec. 12.12	Energy needed to melt a specified mass
WT	Sec. 17.3	Thermal energy
w	Sec. 9.2	Energy dissipation; power
wT	Sec. 12.10, Eq. (12.10.2)	Thermal power per unit surface area delivered by impacting mass
X	Sec. 13.4, Eq. (13.4.3)	Variable of substitution
x	Sec. 3.2	Rectilinear coordinate Iying in the horizontal plane
	Sec. 12.2	Small radius of a toroidal jet stream
x0	Sec. 6.4	Magnitude of the x axis of the epicycle described about a guiding center
Y	Sec. 13.4, Eq. (13.4-4)	Variable of substitution
y	Sec. 3.2	Rectilinear coordinate Iying in the horizontal plane
Z	Sec. 13.3, Eq. (13.3-4)	Variable of substitution

z	Sec. 3.2	Rectilinear coordinate in the axial direction
	Sec. 2.3, Fig. 2.3.1	Sun
	Sec. 2.1, Table 2.1.1	Mercury
	Sec. 2.1, Table 2.1.1	Venus
	Sec. 2.1, Table 2.1.1	Earth
	Sec. 2.1, Table 2.1.1	Moon
	Sec. 2.1, Table 2.1.1	Mars
	Sec. 2.1, Table 2.1.1	Jupiter
	Sec. 2.1, Table 2.1.1	Saturn
	Sec. 2.1, Table 2.1.1	Uranus
	Sec. 2.1, Table 2.1.1	Neptune
	Sec. 2.1, Table 2.1.1	Pluto
	Sec. 17.5	Ascending node
	Sec. 17.5	Descending node
	Sec. 6.8	Dimensionless proportionality factor
	Sec. 7.2, Eq. (7.2.4)	Dimensionless constant
	Sec. 2.2	Ratio of radius of gyraffon to equatorial radius of body
	Sec. 2.2	Normalized moment of inertia (moment of inerffa per unit mass and unit radius squared)

	Sec. 7.2, Eq. (7.2.5)	Dimensionless constant
	Sec. 11.2	Dimensionless proportionality factor
	Sec. 21.2, Eq. (21.2.1)	Specific gravitational potential of secondary body with respect to the primary body
	Sec. 21.4, Eq. (21.4.2)	Value of gravitational potential at which infalling matter can become ionized
	Sec. 5.5, Eq. (5.5.4)	Dimensionless proportionality factor
	Sec. 7.2, Eq. (7.2.6)	Dimensionless constant
	Sec. 16.5, Eq. (16.5.1)	Dimensionless proportionality factor
	Sec. 3.3	Indicating incremental change
	Sec. 6.7, Eq. (6.7.1)	Geometrical factor
	Sec. 12.10, Eq. (12.10.6)	Dimensionless proportionality factor indicating maximum in temperature profile of an accreting embryo
	Sec. 17.3	Degree of ionization
	Sec. 23.5	Dimensionless proportionality factor; the normalized distance (the ratio of the orbital radius of a body to the ionization distance for its primary body)
	Sec. 9.2	An angle
	Sec. 23.1, Eqs. (23.1.4)-(23.1.5)	Dimensionless proportionality factor indicating degree of ionization of infalling matter
	Sec. 9.3	Viscosity
	Sec. 2.2	Mean density of a body
	Sec. 8.3	An angle
k	Sec. 8.2, Eq. (8.2.3)	Constant of integration
	Sec. 3.6, Eq. (3.6.1)	Dimensionless constant

	Sec. 3.2	Meridional angle or latitude
µ	Sec. 16.3	Magnetic dipole moment
µlm	Sec. 16.4	Lower limit of the magnetic dipole moment such that the tangential component of the magnetic field is equal to the magnitude of the total magnetic field strength
v	Sec. 6.8	Collision frequency; number of collisions per unit time
	Sec. 13.1	Moment of inertia
	Sec. 8.4, Eq. (8.4.1)	Libration angle
	Sec. 2.1	3.1415 (ratio of the circumference to the diameter of a circle)
	Sec. 6.8	Density of dispersed matter
	Sec. 2.4, Eqs. (2.4.1)-(2.4.2)	Distributed density (density of a secondary body's mass when distributed along the orbit of that secondary)
	Sec. 2.1	Indicating summation
	Sec. 5.5	Cross section
	Sec. 6.8	Collision cross section
	Sec. 12.3, Eq. (12.3.1)	Capture cross section
	Sec. 15.1	Electrical conductivity
	Sec. 12.7	Cross section of a jet stream
	Sec. 2.2	Spin period of a body
	Sec. 9.2, Eq. (9.2.1)	Oblateness or ellipticity of a body
	Sec. 15.3	Poloidal magnetic flux
	Sec. 4.3, Eqs. (4.3.4)-(4.3 5)	Longitude of proper perihelion
	Sec. 4.3, Eqs. (4.6)-(4.7)	Longitude of proper node

	Sec. 3.2	Azimuthal angle or longitude
	Sec. 6.7, Eq. (6.7.5)	Constant, in number/cm3
	Sec. 11.2, Eq. (11.2.2)	Constant, in cm K/g
	Sec. 7.2, Eq. (7.2.6)	Constant, in units of number times a variable power of mass
	Sec. 7.2, Eq. (7.2.4)	Constant, im units of number times a variable power of radius
	Sec. 7.2, Eq. (7.2.5)	Constant, in units of number times a variable power of cross section
	Sec. 5.5	Energy flux
	Sec. 8.2	An angle
	Sec. 9.3	Rotational angular velocity
	Sec. 13.3, Eq. (13.3.3)	Rotational escape velocity
	Sec. 6.4	Orbital angular velocity

Subscripts
.
c	Central or primary body
sc	Secondary body
em	Embryo
gn	Grain
Lm	Limiting value
0	Initial value or parameter values for the guiding center or circular motion
K	Denoting orbital parameters for a body describing Kepler (circular) motion
A	Apocenter, aphelion, apogee, etc.
P	Pericenter, perihelion, perigee, etc.
	Ascending (and descending) node
x,y,z	Components in the x, y, and z directions
	Components in the r, , and directions
	Sun, Mercury, Venus, Earth, Moon, Mars, Jupiter, Saturn, Uraus, Neptune, Pluto

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