Symbol
Meaning
Typical unit
Introducing
equation
Kn p
Knudsen penetration number
Unitless
3.99
k p , k p ”
Proportionality constants connected to dust
size distributions
4.75, 4.77
k s
Sublimation coefficient
Unitless
2.96
k T
Species type used to indicate different
species
4.43
L
Angular momentum
[kg m
2 s
À1
]
2.32
L 0
Characteristic scale length for conductive
path
[m]
2.119
L Kn, L 0
Characteristic dimension of a gas source
[m]
3.47
L S , L H2O
Enthalpy (latent heat) of phase change (and
specifically for water ice sublimation)
[J kg
À1
]
2.88
L th
Thermal luminosity
[W]
2.12
L th
Thickness of a layer
[m]
3.104
L tu
Length of the tube
[m]
3.105
M
Reactive torque caused by activity
distribution
[kg m
2 s
À2
]
2.31
M(μ 0 ,μ)
Model for multiple scattering within the
Hapke formalism
2.69
M ⨀
Solar mass
[kg]
1.12
m ⨀
Astronomical magnitude of the Sun
Unitless
2.2
m 0
Mass of the individual monomer
[kg]
4.38
m 1
Observed visual magnitude of a comet
Unitless
1.1
m 1,2
Atomic masses of two species
[kg]
3.34
M a
Mean anomaly
[rad]
1.8
Ma
Mach number
Unitless
3.53
m e, m n
Mass of electron (neutral)
[kg]
3.123
m g
Mass of a molecule
[kg]
3.54
m H2O
Molecular mass of water (or another species) [kg]
2.35
m i, m n
Mass of an ion (neutral)
[kg]
3.117
m imp
Impactor mass
[kg]
2.128
M M
Molar mass
[kg mol
À1
]
3.24
m N
Magnitude of the nucleus
Unitless
2.2
M N
Mass of the nucleus
[kg]
1.23
m p
Mass of a projectile
[kg]
7.1
M p
Mass of a planet
2.87
m ref
Refractive index
Unitless
4.27
m ref,r, m ref,i
Real and imaginary parts of the refractive
index
4.27
M s
Sonic Mach number for the solar wind
Unitless
5.22
ñ
Mean motion of masses around barycentre
[rad s
À1
]
1.8
N
A number of observations or objects in a bin
4.83
n 0
Number density of an imaginary sub-surface
reservoir of gas molecules
[m
À3
]
3.80
(continued)
xxviii
Symbols Used
Meaning
Typical unit
Introducing
equation
Kn p
Knudsen penetration number
Unitless
3.99
k p , k p ”
Proportionality constants connected to dust
size distributions
4.75, 4.77
k s
Sublimation coefficient
Unitless
2.96
k T
Species type used to indicate different
species
4.43
L
Angular momentum
[kg m
2 s
À1
]
2.32
L 0
Characteristic scale length for conductive
path
[m]
2.119
L Kn, L 0
Characteristic dimension of a gas source
[m]
3.47
L S , L H2O
Enthalpy (latent heat) of phase change (and
specifically for water ice sublimation)
[J kg
À1
]
2.88
L th
Thermal luminosity
[W]
2.12
L th
Thickness of a layer
[m]
3.104
L tu
Length of the tube
[m]
3.105
M
Reactive torque caused by activity
distribution
[kg m
2 s
À2
]
2.31
M(μ 0 ,μ)
Model for multiple scattering within the
Hapke formalism
2.69
M ⨀
Solar mass
[kg]
1.12
m ⨀
Astronomical magnitude of the Sun
Unitless
2.2
m 0
Mass of the individual monomer
[kg]
4.38
m 1
Observed visual magnitude of a comet
Unitless
1.1
m 1,2
Atomic masses of two species
[kg]
3.34
M a
Mean anomaly
[rad]
1.8
Ma
Mach number
Unitless
3.53
m e, m n
Mass of electron (neutral)
[kg]
3.123
m g
Mass of a molecule
[kg]
3.54
m H2O
Molecular mass of water (or another species) [kg]
2.35
m i, m n
Mass of an ion (neutral)
[kg]
3.117
m imp
Impactor mass
[kg]
2.128
M M
Molar mass
[kg mol
À1
]
3.24
m N
Magnitude of the nucleus
Unitless
2.2
M N
Mass of the nucleus
[kg]
1.23
m p
Mass of a projectile
[kg]
7.1
M p
Mass of a planet
2.87
m ref
Refractive index
Unitless
4.27
m ref,r, m ref,i
Real and imaginary parts of the refractive
index
4.27
M s
Sonic Mach number for the solar wind
Unitless
5.22
ñ
Mean motion of masses around barycentre
[rad s
À1
]
1.8
N
A number of observations or objects in a bin
4.83
n 0
Number density of an imaginary sub-surface
reservoir of gas molecules
[m
À3
]
3.80
(continued)
xxviii
Symbols Used